Power Window/Power Seat Circuits Crossed?
 

Starting a new thread since the issue in my 87 Cabriolet is no longer a battery-drain as described here: http://forums.pelicanparts.com/porsche-911-technical-forum/848015-battery-drain-87-cabriolet-not.html, it's determining why the power seat circuit (fuse 2 on block 3) is energizing my power window circuit (fuse 1 on block 3.)

With both fuses in, the power windows work all the time, even when fuse 1 and the power window relay are removed! Oddly, this condition is also causing the PW relay to stay energized at all times, resulting in a 90mA drain.

When just fuse 2 is removed, the windows work as described in the manual, i.e., they work with the key on, and when the key is removed until a door is opened. When the car is parked the drain drops to an acceptable 10mA.

As noted in the other thread, Fuse 2 is for the "seat adjusters" and "booster fan" according to the fuse panel label. I noted on the "Seats" schematic 970-44 that both the red/blu and red (always hot) wires have close proximity, though it appears that the red/blu is for the seat heater circuit, and my car doesn't have them. Also noted two symbols on the schematic labeled "J/C (Blue Tape)" and "J/C (Red Tape)" - what are they and where are they? Also on the drawing, below J/C (Blue Tape) there appears to be a connection between the red/blu wire and a red one - am I reading that right, and if so, where might I find that?

It's clear that my car's wiring has been at least slightly molested (there are a number of wires-to-nowhere and a couple of unrelated splices in the frunk) but there a no obvious signs that either of these circuits have been messed with.

One clue - the driver's side seat adjuster has a button missing, and I'm inclined to disconnect it to see if damage to the switch is crossing the circuits. It looks like the seat has to be removed or at least unbolted and raised to get at the connections underneath. If that doesn't do it, the next step is to see how the seat wires are routed to look for crush or cross-points.

Any wisdom or suggestions would be most appreciated.

Thanks,
GK

Sent you a PM. If my offer will help, PM back your email address and I'll reply back with the diagrams.

When I wasn't prepping for blizzard Juno today, I took a few minutes to follow steely's advice from the old thread:
- Lifted the driver's seat (there's a fun job...) and located the seat adjuster switch plug and pulled it; disconnected the seat-belt switch harness (just because I could); figured out how to disconnect the passenger seat adjuster control plug without lifting the seat and did so. No joy. This was a long-shot as the Bentley schematic 970-44 shows the red/blu wire feeding the seat heaters (which I don't have) and not the seat adjusters.

- Still following steely's advice, I disconnected the red wire and the red/blue wire from fuses 2 and 1 respectively. There's no continuity between the screws on the fuse block, which is good, but indeed there are 0 ohms between the red and the red/blu wires, which is bad, and the essence of my problem.

Next step: follow the black fabric tape-wrapped wire harness from behind the fuse block as it snakes its way under the fuel filler toward the dashboard. I'll be looking for signs of splicing or pinching. I'll also be looking for the "J/C" objects noted on the schematics.

My windshield wipers won't park, so I might be taking out the ductwork and blower to access the wiper relay and get a good visual on the black-snake-harness while I'm at it.

Additional thought: My fuel pump runs continuously when the key is on even when the car isn't started. I believe that it's supposed to only run for a short period before shutting off if the car hasn't started. I'm wondering if this is a related issue or just a coincidence.

I'm wondering if I need to pay extra attention to this mess of wires just below the fuse panel, under the fuel fuller pipe:
http://forums.pelicanparts.com/uploa...1422228806.jpg
If anyone sees a smoking gun here, let me know!

thanks,
GK

Hi GK, nah, you shouldn't hear the pump, and I wonder too if it is related.

When you start the car, the DME gets powered and tells the DME relay to furnish power to the pump by using power from the IGN. If the car doesn't start, and you let go of the key, the relay relaxes/de-energizes and relay killing FP power. If the car starts, the DME looks for good speed/reference signals and uses this logic (that the car is actually running) to keep the FP relay closed/energized (in lieu of the IGN power). I can dig out the real operational concept if you want.

I only see 2 items of interest in the pic - one a missing screw on a fuze terminal and the other a potentially exposed wire circled below.

I will try to look at my schematic based on the new info (no heaters, a persistent fault with the seat unplugged, and a semi-hot wired FP).
http://forums.pelicanparts.com/uploa...1422238215.jpg

I checked my diagram and my fuse block for my car and the one Dan circled with the missing screw is your fuel pump fuse. The wire coming in the top should be the wire from the main harness IIRC. I had that particular wire pointed to when I removed the harness from my car a long time ago.

On my 85, the wire from the harness to the top of fuse 3 (missing lower screw) is red/green. It appears to be solid red coming in the bottom where the screw belongs. Let me know if I can take any pictures of my fuse block that might help you sort this out.

Any chance you could post a pic of your fuse block showing the top wires in?

Do you or did you have a power top? I think it ties in to that circuit also.

Fuses.
 

Hope this helps:

http://forums.pelicanparts.com/uploa...1422288669.jpg

http://forums.pelicanparts.com/uploa...1422288697.jpg

http://forums.pelicanparts.com/uploa...1422288743.jpg
^^^^^
You will need to print/cut/paste.

Good luck,

Gerry

Thank you kindly for this. I'm focusing on this part of the middle diagram:
http://forums.pelicanparts.com/uploa...1422295004.jpg
Can you provide some insight into what the abbreviations on the right side mean, and what is meant by "welding point?" I'm guessing that this may help me find the physical locations of these wires and junctions.

I'm also noting that I have a fuse and wires attached to fuse 3 in block 3, which the diagrams say are for headlight cleaners and the power convertible top, neither of which are on my car.

Thanks again,
GK

The welding point is a distribution point for power. They are designated with Roman Numerals. I do not know if they are a hard point somewhere (like they are for the ground points), or if they are simply a grouping of splices. So for Fuse 1, welding point XII may consist of 3 wires (as an example and I may not be accurate), one from the fuse, one to the Sun Roof, and another to the Seat heaters.

In the string of abbreviations, the first is the wire diameter in mm^2, the color using German abbreviations (RT/BL for Red/Blue), next the NR or number of the branch (2/60 is a big one), then the welding point, then a reference/flag pointer to the schematic sheet where the welding point can be seen. All of the sheets have an alpha numeric grid system with letters running horizontally, and numbers vertically. I can't make the characters out for the Fuse 1 example. If for example it said G20, you'd go to the schematic sheet with G20 on it.

It's a neat system, and a lot of mechanical assy dwgs in the US use the same method, only we call them zones instead of grids.

I found somewhere that the earlier german schematics referred to the ground points as "masse punkt', so you might see some gnd points referred to as "MP".

I therefore wonder is Welding Point was a literal translation for something else that I would consider a junction or 'butt splice'. I can't find anything about it on the interwebz about as I try to teach myself.

The weather (juno) is keeping me a little busy too - but so far it hasn't turned out to be half as bad as they said it would be near Phila where I live. But there is always tomorrow.

That said, I didn't get to far in looking at the dwgs, but I did find a diode that I wondered about.
I hate to have you needlessly perform tests, but if you get a chance, can you re-perform the resistance measurement you made yesterday on Fuse 1 to 2 on block 3 - with the fuses out and on the load side (bottom)?

But do it twice to see if there is a diode between them by flipping the leads.
This is a complete guess on my part, so you don't have to try this before I or someone else confirms.

It may not prove anything if I am wrong.
You would do + lead to F2 and (-) to F 1, read, then flip the leads (-) to F2 and + to F1.
If you get a short in both directions, there is no diode there or if there is, it shorted (got old).
If you get diode action, or a short in one direction and an near open in the other direction, you'll still have to hunt some more. (that would show a diode there , and it wasn't the cause of this problem).

BY the way - if Gerry is looking at this, so much the better!

I am hoping that in the meantime I can confirm if the diode is supposed to be there or not.

Gerry, Dan, Cabmando, Rick - Thanks for taking the time to help me solve this puzzle. I love these little missions, I always end up learning a lot.

Dan - I did the test you asked, and there's effectively no resistance between the wires on the load side of fuse 1 and fuse 2 on block 3, regardless of which test lead is connected to which terminal.

Rick - No, I don't have a power top, seat heaters, or headlight washers. Part of the puzzle here is that there's a fuse 3 in block three which is supposed to be for the top and headlight washer.

As Cabmando noted, the fuse with the missing screw is supposed to be for the fuel pump as shown on the fuse panel label. There's a taped-off red wire just underneath it, perhaps the original fuel pump lead? With the battery connected and key turned on, there's no voltage at the power side of this fuse (fed by a red wire w/green stripe). The DME was replaced by the PO (and looks new) and the DME relay was replaced by me. Perhaps another wiring snafu that caused a PO to hot-wire the fuel pump, or does the DME or DME relay need the resistance of the FP to activate?

The item circled at the bottom is not an exposed wire, it's a red wire that appears to emerge from the black-fabric-snake wire harness, and what you see there is a splice to a red wire with a yellow stripe, which snakes its way behind the fuse blocks and is attached on the power-side between fuses 8 and 9. Thinking this might have been the tap for the fuel-pump hot-wire, I disconnected it, but with the key turned on, I could still hear the FP running.

Cabmando: You had asked for better pics of the top of the fuse blocks - here are a couple, hopefully these will suffice - if not, I'll snap some more! Here's the left side (fuses 1,2,3 are pulled) and you can see the taped-off red wire below and to the right of the missing screw. You can also see the red wire w/yellow stripe tap described above: http://forums.pelicanparts.com/uploa...1422325237.jpg

Here's the right side:
http://forums.pelicanparts.com/uploa...1422325345.jpg

I'm hoping to have some time in the AM to chase that wire harness up toward the dashboard, at least until Juno finishes dumping on us, and then my day's work will be cut out for me...

Thanks again brother Pelicans!
GK

Thanks for doing that resistance test again.
I looked at the schematic for an obvious cause of the sneak path from F2 to F1, and can't figure any out - other than the possibility that a PO in inadvertently swapped a wire between the red and blue tape.
On the schematics they are drawn as jumpers/connectors with 4 M/F pins/jacks, but I don't know the location.

A portion of the schematics or work shop manual that I do not have unfortunately is the chart that shows the 3-space xyz location of devices and harness connectors.

Power leaves F1 for the windows, the sun roof you don't have, and the seat heaters you don't have either - these are all common to the mysterious blue tape connector.
The power from F2 feeds the A/C, the footwell blowers, and the seat adjustment -and is common to the Red tape connector.

With the short on the load side between F2 and F1, the F2 power would furnish power to the windows, completely bypassing the window control relay, and in fact, leaving it on (when it is plugged in). You found this, but I wanted to confirm for myself from the schematics as a possible mode.

So, we're back to where we started - a possible short between the F1 and F2 in the harness or just maybe someone jumpered the red and blue taped connectors. Another chance is that the short could be inside the 8-pin seat connector on the harness side. If the seat adj power touches the seat heater ckt insde of the backshell of the connector -badabing.
Porsche wired the harnesses near completely, even if you didn't get the heater option in the seat.

For the fuel pump, the disconnected / taped red wire used to go directly to the pump from the bottom of fuse F3. I wonder if the other end was dead-ended at the FP?

The Red/Green wire should come from the DME relay to the top of F3, and this is what you found. It will be dead with the key ON. It will only go Hot when starting or running.

Can we say that when you measured this Red/Grn wire with the Key ON and found it dead - was the fuel pump running? Can you check it with the car running? That might show that the DME FP control is still working albeit unused.

sorry if I am repeating myself or if you already answered this above.

BTW - I mentioned earlier that the welding points are for power distribution, it looks like they can be used for GND distribution as well.

good luck in the snow tomorrow - I hope it isn't as bad as they're calling for.

Dan -
Thanks for thinking this through, and for being so methodical in your approach. Indeed I did not test the red/grn wire on fuse 6 with the motor running, but will do so. It makes sense that the car would have to be running for the DME to provide power on that lead. At some point I'll have to get under the car to see if there's another dangling wire near the FP, or search for a jumper somewhere upstream. It would seem like a common hack to bypass the DME relay permanently in this way, but I'd rather restore this to the way it was intended to run (and carry a spare DME relay...)

I'll check the innards of those 8-pin connectors at the seats for a possible short there as well. The seats on this car have been out before, so you never know who mucked with what. I also want to chase the wires from those connectors up toward the firewall to see if there are any pinch-points or obvious hacks.

While I'm getting up-close-and-personal with my car's wiring, I find it disconcerting that there are so many loose connectors/wires-to-nowhere up front. Could they all be for the headlight washers and high-intensity window washers that I don't have? Also - the black wire on the power side of fuse 1 seems to be rather small in size considering it provides power to a 25a fuse, and the red/blu wire on the load side is easily twice as thick.

Luckily Juno dumped about 10 fewer inches on us than expected, but I've still got 8" of powdery snow blowing around out there to clear. At least we avoided The Big One!

Thanks again, I'll be reporting back on progress and/or other clues.
GK

Could there have been a jumper created at the DME relay to power the fuel pump when the key comes on? It would be interesting to know what fuse kills power to the fuel pump since it can't be the one that was designed to do it.

fuse Panel Wiring-MY 86.
 

http://forums.pelicanparts.com/uploa...1422379127.jpg
^^^^^
With the exception of the fog lights (grey/red-spice) wire modification,
here is the correct stock fuse panel wiring.

G.

That's strange, your fuel pump fuse (6th from the left) appears to have two wires on the bottom side. My 85 does not.

GK - glad about the snow reprieve - we got 3or 4 inches, instead of 8.
The F1 wiring gage difference is correct, although I don't know why the size difference either. The snippet of Gerry's schematic in your post #8 shows 2.5 mm^2 SW (Schwartz) in, and the larger 4.0 mm Red/Blue. That, and the pic from Gerry show yours to be stock.
Maybe rick, Gerry, Cabmando know - perhaps it is larger to permit splicing downstream (more physical wiring technique than a current handling question?).

I too have found some orphan wires in my care, but they are usually terminated to unused connectors). Although I haven't had a need to search for them, so maybe I have more and don't know it. I also don't think my wiring was changed, especially around the fuse boxes. Sorry I can't respond with a class-1 answer on the washer wiring. Do you know if you had this stuff once and it was removed?

Bingo! the fuel pump fuse should only have 1 wire on each end.
The fuel pump should only run while cranking 'START' and then the DME keeps it activated once the engine catches.

Investigate the mystery wire on the fuel pump fuse, most likely it's back feeding the pump. Also unplug the DME relay, does the pump still run? it should never ever run with the DME relay unplugged as it's not possible in the stock wiring configuration.

Do those tests and we go from there

+1

I'll have to look at this to refresh my thin memory to see how the DME gets power.
If the PO didn't rob power at the fuse box somewhere, the DME would be a next choice since it's so close to the relay. There was a neat article on the DME logic (diode or'ing) to the DME replay I found once on dorkiphus.net that explained it.

By the way, if you didn't know, the clear-ish plastic housing behind the lower red circle in your pictures is a J-Connector - a FASTON connection grouping. The Weld Points are more like crimp type butt splice groupings covered with a plastic or heat shrink protector (example in my photo to the right of the green vertical tape). Here is a sample showing the main Red/Blue feed going to the Weld Group and the J-Connector. This is from my 1985.

http://forums.pelicanparts.com/uploa...1422392864.jpg

That Dorkiphus thread regarding DME is a great resource:

http://dorkiphus.net/porsche/showthread.php?t=16859

Regarding your comment about the relative sizes of the black wire on top of fuse 3-1 and the much larger red/blue wire on the bottom of the fuse, I can only comment that we don't get off easy with this car wiring scheme. That large blue/red wire (on my car anyway) goes only a few inches before it branches over to a few other (see my photo).

It probably started out straight forward wiring scheme on the very early cars. By the time ours were made, there is now a convoluted scheme that morphed over time as new systems were continuously added. I got tired of trying to sort it out and pulled the fuse block completely. I am stripping the car back to basics and rewiring mine using buses and straight forward fusing and relays (once circuit per fuse type of approach that does not use the ignition switch and or any other switch for major power distribution). I have been scratching my small brain about this for months and am finally getting it together. I couldn't stand back and understand the overall scheme - it is too complex. I had to take it circuit by circuit and understand each circuit as a stand alone.

Here's the DME relay power schematic.
http://forums.pelicanparts.com/uploa...1422393103.jpg

http://forums.pelicanparts.com/uploa...1422393117.jpg

Thanks Gerry. I may come back to you and ask for a little clarification or confirmation as to what colors/stripes are on some of those. Your relay layout and number looks a little different than mine but Bentley indicates that, aside from relays, the 86 and 87 should be identical (barring the "subject to change" disclaimer.)

Thanks again for this.
GK

I'm doing this next. It may not fix my power window relay mystery, but then again, it might!

THX
GK

After I look for a fuse that disables the pump when pulled, I'm doing this. Excellent suggestion, thank you.

GK

Thanks for the explanation about the J-connectors. I was looking at that thing last night and wondering if that's what it was. I'll have to see if I can get better access to it - it's wedged in that spot - and see if the wires are crossed or shorted.

I am by no means a wiring expert, but I agree with you - the wiring in this car has the look and feel of a basic system that's been added-on to time and again. On the up-side, it's all pretty accessible and relatively easy to lay eyes on. I'd never have the big-brass-ones to pull it all out and start over like you did though... There's the temptation to just button it back up and leave as is, but I'm a little too OCD to live with something that's not working as designed, and the fuel pump issue is a safety issue.

Thanks again!
GK

Today I love my snowblower almost as much as my 911...

On that black wire feeding fuse 1, I see what you mean, and I can at least be confident that it's "correct" even if it doesn't look right to my uneducated eye.

I guess if the orphan wires are terminated by a connector, it's just part of the harness that's not used for my lightly-optioned car. If it's taped off, it's a sign of corruption... As far as I know, there were no features that were removed. I believe the front bumper and valance to be un-original, and I wondered if it might have had headlight washers, but there's no headlight washer switch inside. This car has a few little mysteries like that.

Thanks to you gents I've got some good directions to pursue. I'll be reporting further on this mystery once I've gathered more clues...

Thanks again!
GK

[QUOTE=scarceller;8458595]Here's the DME relay power schematic.

http://forums.pelicanparts.com/uploa...1422393103.jpg

Power from the ignition switch comes in on the line to connection 86 and powers the right hand coil in the diagram. It exits through 85 on the brown wire to ground.

This lets unfused power from the Battery + in on the large red wire at relay connection 30. This power flows out connection 87 to the DME, powering it. It also flows though the left hand coil closing that relay. The closing of that side is controlled by the DME through the ground of that coil wire 85b. Once the DME closes that ground and the left coil is energized, the the power in from 30 is now routed to power the fuel pump out connection 87b. It flows to Fuse 3 and then to the pump. If you pull Fuse 3 then your fuel pump should not run. Based on the schematics above, it should be Red/Green wire on the top of Fuse 3 and Red on the bottom.

On my car (late 1985), that large red unfused fuel pump power feed is a ring terminal connection at the battery + terminal. It is encased in black protective tube so that it looks like a black wire. It routes down between the tank and the tub below the fuse block.

So, if the DME relay fails, you can jumper 30 and 87b to bypass the DME relay and get the fuel pump working.

For your fuel pump to work, assuming normal wiring, whenever the key is switched on, both coils would have to close. You either have a jumper in there somewhere, or the ground control wire 85b is hard grounded (or DME module fault causing a hard ground), or someone has moved the wire to the fuel pump that is downstream of the DME relay to switched power location (at the fuse block?). The fact that your first photo showed no wire on the output of Fuse 3 says that maybe someone has moved that wire to a switched hot location. The power for the fuel pump comes in at the top of the fuse block and out through the bottom. I would look for that red wire that is moved to a location of switched power.

If it was me, I would be checking this wire here (in blue):

http://forums.pelicanparts.com/uploa...1422422018.jpg

Is that a red medium gauge wire in electrical tape? That could be the fuel pump wire as well (correct gauge and it could fit at the lower fuse location. If it is, then someone got real creative with your fuel pump wiring.

The other area in green and the fuse to the left of it - there should only be one red feed for the cabriolet top. There are two up there and that is switched hot feed. I would check those next. Pull them one at a time, isolate them, and see if the fuel pump works.

Thanks Mike,
I agree, that taped-off red wire is a red flag, it will be one of my avenues of investigation. I may start at the FP and try to work my way back.

Regarding the leads that you circled in green (fuse 8 on the middle block) the diagrams indicate this:
http://forums.pelicanparts.com/uploa...1422454558.jpg
...and the power top is powered by fuse 3 on block 3. Regardless, There's a big red wire on the power side of fuse 8 that isn't accounted for in the diagram. In addition, I don't have a power top or headlight washers and still my car has connections to fuse 3.

I wouldn't be surprised to find some "creative" solutions in this car - the PO used to take it to one of those national chain tire stores whenever he had issues with it! Lucky for me, I really like solving puzzles.

After spending the day moving snow yesterday I had lost my initiative for wire-chasing, but it could be a busy night in the garage tonight.

Thanks!
GK

Unplug the DME relay and turn key to 'RUN', does the pump run? If so it's not the relay nor the DME.

After looking at your picture of the fuses I see a issue, the 3rd fuse from the left (blue fuse) is the Fuel Pump fuse and it's missing the screw and the wire at the bottom that feeds the pump! Looks like someone moved the FP wire else where! The red wire at the top of that fuse comes from DME Relay pin #87b. That missing wire is your problem!

And the 4th fuse from left with the cut taped wire is for Brake Lights and Cruise Control.

I have a theory (hunch) what may have been done, they may have removed the factory alarm from the car and if this is done the pump will never run when key goes into 'START' and they did not know howto properly fix the issue. So instead they simply moved the FP wire to a fuse that always has power in 'RUN' and 'START'. Was the factory alarm module removed?

As already mentioned, fuse #8 from the left looks odd. I bet that the red wire at the top is the FP feed that was relocated from Fuse #3.

If the alarm module is removed you must jumper these 2 pins as shown in this picture I marked up:
http://forums.pelicanparts.com/uploa...1422459533.jpg

That's an easy test, and I'm adding that to my list of tactics, thanks.


Agreed. The remaining questions are, 1) where is the red wire that feeds the FP? (Probably tapped into the power side of the fuse panel) 2) What were they trying to "fix" when they did this? (and there are many potential answers to that...) As far as the taped wire goes, I think there is already a wire attached to that 4th fuse, but I have to look at it again in person, photos can be deceiving.

The module is in place, but I'll have to look for cut or bypassed wires going to it. It could also have failed, necessitating a bypass.
Thanks for the suggestions, much appreciated!
GK

GK, the FP wire may be one of the red wires sitting at the top of fuse #8 now. My bet is that the pump will run with the relay out, if so then remove the 2 wires from fuse #8 does it stop running?

Kudos to Sal and Mike for spotting the culprit, i.e., the tap on top of fuse 8:
- I disconnected the fuel pump relay and as Sal predicted, the fuel pump ran with the key turned on;
Referencing this pic with Mike's highlighting:

http://forums.pelicanparts.com/uploa...1422422018.jpg

- I removed the red wire on the power side of fuse 11 (fuse 8 on block 1, the pink fuse) and the pump did not run with the key on;
- Followed that red wire down behind the fuse panel and under the filler neck, and found where it is spliced into a harness here:

http://forums.pelicanparts.com/uploa...1422500961.jpg

You can see the red wire that's connected to the fuse panel is spliced to a red wire that leads into a black plastic sheath that leads toward a hole in the frunk floor, apparently headed to the fuel pump. Also in that sheath are two brown wires and a light weight red wire w/ white stripes that's simply cut.
The brown wires in the sheath are spliced to two brown wires that lead to the grounding point on the inner fender near the fuse block.

As far as the taped-off red wire (circled in blue above) I can only trace it to the point at which it enters the black-fabric-wrapped harness immediately behind the fuse block.

Next steps:
- The taped-off red wire still seems like it ought to go to the FP - I think I need to jack the car up and look at the wiring underneath for more clues. The splice job I found might not have been into the original fuel-pump harness;
- I see at least three other points in that maze of wiring near the filler neck where there are other splices, i.e., crimp connectors wrapped in tape. There was clearly some improvising going on here at some point, and it's a bit disconcerting. I may be in for a little more than I counted on...
- I suppose I could take that red wire that I now know is connected to the FP, attach it to the load side of fuse 3 (with the missing screw) and see if the car starts and runs, and if the fuel pump runs only when it's supposed to.
- Back to my original quest to figure out why the power window relay is always energized, I took a close look at this connector which, thanks to SpyderMike, I now know to be a J-Connector:

http://forums.pelicanparts.com/uploa...1422502075.jpg

What's confusing to me is that Bentley schematic 970-44 shows two separate connectors and seems to indicate that the red wires from fuse 2 are isolated from the red/blu wires from fuse 1. In the J-connector in my picture, the red and red/blu wires seem to be all connected together! How could this be correct if the effect is to bypass the power window relay since the power to the red wires is always on?

Thanks again for your help - the quest continues...

GK

Hey, this beats watching TV!

Why someone did what they did is a mystery. Maybe they cut the wrong loom (all of the wires in the loom you show have been cut) and it cascaded from there. Unfortunately I am 1000 miles from my car for a while. It has the wires for each system separated by circuit at this time and it would be easy to help you further.

Check out this photo for future reference if needed:

http://forums.pelicanparts.com/uploa...1422504355.jpg

The wires that go to the DME relay from Batt+ seem to go between the fuel tank and tub then through the smuggler's box. The other wire loom in the photo is going full width side-to-side are the brake warning wires. The wires to the fuel pump from Fuse 3 go down through the hole where all the other aft routing wire looms go (in front of the brake MC Booster).

My notes show a small red/white routing to the bottom of fuse 1-7. It seems like your issues might have to do with the wiring related to that fuse. Take a look at the fuse block diagram up earlier in this thread. The outgoing wires on fuse 1-7 should be red/white.

Let's take it circuit by circuit. Finalize the fuel pump issue and then let's see what else isn't working....just an idea.


Mike

If I get bored painting a ceiling (or maybe I should say "when") I'll go out and pop the frunk and see what I can find for the connectors in that area. Mine is luckily pretty unmolested so I might be able to add some pics for comparison.

Either way it sounds like you're on the right track with the fuel pump mystery.

The wire from the fuel pump '+' MUST go to the bottom of Fuse #3, that's the stock config.

Next test just for fun:
Measure the voltage at top of fuse #3 (it has a red wire at the top) that wire goes back to DME relay 87b. Leave the meter on this wire and then remove the DME relay and jumper pin #30 to 87b at the relay harness (no need to even put key in ignition). Once jumper is in place do you have 12vdc at fuse #3? If so we are good. And we'll move to next steps.

If you wish to really fix the wiring back to stock you MUST locate the solid RED wire that feeds the pump, this was the wire removed from bottom of fuse #3 and I bet it's one of the red ones at the top of fuse #8. Remove one at a time from fuse 8 till you have the RED wire IDed and then put this wire back on fuse #3 and we'll go from that point.

My theory on what was done: Back in the 80s and 90s aftermarket alarms were very popular and often when installing these they mucked with the factory alarm and messed up that alarm module connection to the DME relay. Find the alarm module and look closely to see if they cut into any wires on it, particularly that black wire that goes to the DME relay.

Thanks Cab, I'm especially interested to see if you have the J-connector in a similar place. BTW - I've got a ceiling waiting for my attention as well, tis-the-season for such indoor projects, so naturally I'm out in the garage!
THX
GK

I agree, it DOES beat watching TV except for the part about being warm. Who doesn't like a good mystery though?
Thanks for the pic - sorting out that spaghetti would be so much easier with the gas tank out (and I've been tempted....)
I'm wondering if that thin cut-off red/wht wire is a clue or just a diversion. I suspect that chunks of the existing harness were re-purposed, so that sheath with the two browns, one red, and one red/wht might have been for something else entirely, and was re-jiggered to feed constant power to the FP. The only other thin red/white wires I can find are for the windshield wipers, and they are working (they just don't park or do intermittent.)

Another example of apparent re-purposing: The two browns on the side of that splice that lead to the grounding point are fabric-wrapped with 4 other thin brown wires that were cut:
http://forums.pelicanparts.com/uploa...1422542375.jpg

Which leads me to think that somebody is being deprived of a ground connection, or replacement grounds were improvised, or somebody had chunks of wiring harnesses from other cars laying around... This is like electro-archaeology.

I'm tempted to remove all the electricians tape that I see, and really get to the bottom of this. I know it's probably best to focus on one circuit at a time, but the big picture might help as well.

Thanks for the input! I'm going to keep at it until it's resolved (in the season finale!)
GK

This ^ is an excellent suggestion - this will be my next step. All evidence to this point suggests that the red wire on top of fuse 3 is coming from that relay, but diligence counts. This will prove that continuity without me starting the car.

Getting the wiring back to factory specs in total might be something I do piece by piece - I'll be satisfied to get the FP and power windows powered properly for now. You were right, that red wire at the top of fuse 8 leads to the FP via that splice, but I want to get under the car and prove it without a doubt. I also want to see if the taped-off red wire under fuse 3 might have been the original lead to the FP, if it's possible to determine that. If so, I may put the original one back into operation.

Checking the alarm module will be my 2nd next step. I'm pretty sure it's a factory alarm system, but you never know. As I've been getting intimate with the wiring in my frunk, I'm noticing a lot more black vinyl tape, so even if the wires aren't cut at the module, they might be cut further upstream closer to the fuse panel.

Were there common failure modes of these factory alarms? It woud be terrific to get the alarm system working as designed, though certainly not a necessity for me.

Thanks very much for the insight and the help, it's much appreciated!
GK