'82 911 Major wiring issues--Advice?

[Dogbreath]

I recently bought a 1982 911SC that was headed for the recycler and I am now discovering why it was.

The wiring has, what appears to be, years of changes and modifications attempted by unskilled installers. There appear to have been stereos and alarm systems installed at various times.

At this point, there are problems with pretty much every electric component. Currently, the following things that do work are:
The brake lights, the emergency flashers, the wipers, the parking lights on the drivers side, the dashboard lights and that's about it.

The electric windows, sunroof, headlights, signal lights, interior lights, windshield washer, etc. are not functional.
In addition, I was told by the PO that they had to use some type of by pass on the fuel pump to get the car to run because the alarm system is connected to it. The car starts and runs fine at the moment.

I have searched numerous sites and tech articles and have wire diagrams but the issue I have is that I do not think anything is at a baseline starting point to troubleshoot.
There are wires spliced and cut and hanging all over the car. The fuse panel looks like it has been altered as well. I have attached a picture below.

I am looking for some advice as to the best way to start. Should I pick one thing, like the headlights, for example, and try to get them to work or should I try to get the fuse panel back to factory setup and then troubleshoot the other components from there?

Thank you for any advice you can provide.

Also...if anyone has a photo of an unmolested fuse panel or any other drawings or photos of how various things are wired I would greatly appreciate it.

Thanks

[fred cook]

If you will send me your regular email address, I will send you an excel file that I built with detailed fuse box info for your car. I also have a colored full wiring schematic in my Porsche factory manual that I might be able to copy for you. You are probably going to find most of the problems at the fusebox or under the dash.

[boyt911sc]

After you received the wiring diagram/s from Mr. Cook, start reading it and familiarize yourself with the following:
a). 21-fuse panel located in the trunk compartment including relays.
b). 3-fuse panel located in the engine compartment plus relays (if any).
c). 14-pin connector located in the engine compartment.

With the collective efforts of members from this forum, we could get the wiring set-ups back to original configuration. Pictures would help a lot in our communication and be specific with your questions. One last question: Is the oxygen sensor and ECU unit being used now in your car? Keep us posted.

Tony

[nineball]

while you are at it buy one of fred's new and improved fuse panels.

[fred cook]

I think that you have almost gotten the fuse panel straightened out. I believe that there should be a black wire from the bottom of fuse 21 (towards rear of car) that feeds the power window relay and a black wire from the bottom of fuse 18 to the trunk light. You currently have a red wire attached to the bottom of fuse 4 that I don't recognize. Try putting 12v on the two unidentified black wires and see if either the trunk light (must turn on parking lights and open the light cover) or the power windows work. For the time being, I would disconnect the red wire on the bottom of fuse 4 until it is identified. Fuse position 20 which is bad was for the a/c evaporator motor and for the front condenser fan. Together they pull almost 25 amps which is why that fuse holder is melted. I split the a/c load between fuse 19 and 20 (one fan on each) to reduce the load. Fuse 19 was for the front headlight washing system if equipped.

[fred cook]

The last relay towards the back should be red. It is for the fuel pump. The black ones will work but are not designed for that job. The relays/positions from front to back are:

1 - blank
2- fog lights (black)
3 - horn (black)
4 - blank
5 - windows (black)
6 - blank
7 - fuel pump (red)

[Dogbreath]

So after many hours of tracing wires to what appears to be there proper locations using a combination of Freds spreadsheet, the Bentley Service Manual and the wiring diagrams provided in the PP Tech Forum and and making reapirs to ones that appear to have been installed incorrectly I appear to be making very little progress. I have the parking lights, wipers, brake lights, back up lights and intermittently the signal lights working. I saw life from the headlights one time, not sure why only that once.

In addition, I had the speedo out to replace the drive gear and when I put it back in, using the wires in the positions I had marked, I turned the key I heard a pop and could smell smoke coming out of the speedo. Now it flutters around 150+ mph when you first start moving and then pegs the needle against the stop and just stays there. Once you turn off the key the needle goes back to 30 MPH.

Any ideas or advice would be much appreciated.

[Arne2]

Ugh! Not sounding too good yet. Where do you live? Trying to help troubleshoot via Internet forum posts is tough, at best. Perhaps there is an electrically-minded Pelican (or two) who live close by and may be willing to assist in person?

[rattlsnak]

Dont give up! Take your time and be methodical. It will happen. It pi$$es me off to no end when I see wiring like this. On the other hand, I have made a nice career repairing issues like yours above!

I recently pulled this out of my project car:

[GothingNC]

Did SC you pick that SC up in Pittsboro?

[Dogbreath]

Yes sir. Are you familiar with it?

[Dogbreath]

Well do, Rattlsnak. I will keep chipping away at it.

[Dogbreath]

Update...today when I started the car I can make the speedo needle bounce if I activate the sunroof switch.
I have a red wire coming from fuse #14 that goes to the sunroof switch but I can not confirm that is correct. The Bentley Manual does not show wiring for the sunroof anywhere that I can see.
Does anyone know if the red wire on #14 is correct?

Also, I have determined that I am not getting voltage to the fuses where the headlights connect. I am about to take apart the High/Low switch in the steering column to confirm the wiring is correct.

Thanks

[rattlsnak]

just making sure you know that the headlights only come one when the key is in the run position.

[GothingNC]

Originally Posted by Dogbreath

Yes sir. Are you familiar with it?

I remember seeing it posted on CL.
Good luck, seems like you got your hands full.

[fred cook]

Originally Posted by Dogbreath

Update...today when I started the car I can make the speedo needle bounce if I activate the sunroof switch.
I have a red wire coming from fuse #14 that goes to the sunroof switch but I can not confirm that is correct. The Bentley Manual does not show wiring for the sunroof anywhere that I can see.
Does anyone know if the red wire on #14 is correct?

Also, I have determined that I am not getting voltage to the fuses where the headlights connect. I am about to take apart the High/Low switch in the steering column to confirm the wiring is correct.

Thanks

My SC has that same red wire. However, it is the one wire that I could not figure out! I left the one attached when I changed the fuse panel in my car. The only things electrical that do not work in my car are the seat belt warning light, the brake warning light on the dash and the cruise control (servo is out of car). I'll take a look and see if I can find anything on it.

[fred cook]

Fuses 13, 14 and 15 are jumpered together on the top side. In the Porsche factory wiring schematic there is a red/white wire that pulls off 13 and goes to the windshield wipers, but nothing off the bottom of fuse #14. Hope this helps.

[Dogbreath]

Originally Posted by fred cook

Fuses 13, 14 and 15 are jumpered together on the top side. In the Porsche factory wiring schematic there is a red/white wire that pulls off 13 and goes to the windshield wipers, but nothing off the bottom of fuse #14. Hope this helps.

Bentleys shows
Fuse 13 bottom side Blu to Fresh Air Blower switch and Red/Wht to WindShield Wiper Switch.
Fuse 14 bottom side Blk/Vio Outside Mirror switch and Fuse 15 bottom side Blk to Tempostat Relay and Grn/Blu Brakelight switch.

On the Top Side of 13-14-15 Bentleys only shows Red/Wht Power Window Relay and Red Yellow Ing Switch

I took the Red/Blk from the Speedometer and Red/Wht to Power Window Relay from the Top of 13 based on your SS.

Do you have a sunroof on your car? If so do you know where the Red from the switch ends up on the fuse box?

Thanks

[fred cook]

Originally Posted by Dogbreath

Do you have a sunroof on your car? If so do you know where the Red from the switch ends up on the fuse box?

Thanks

My car does have the sunroof. I will pull the factory manual tomorrow and take a look for the wiring routing for it.

[Dogbreath]

I am wondering if this could be the root of some of my issues.

In the picture is the Fuel Gauge. As can be seen, someone has rewired the primary ground connector with a very thin gauge non copper wire. This thin wire is used on fuel gauge (as can be seen in the background), oil pressure guage and then is also used on the ground connectors on the Tachometer as well and is eventually spliced into the original ground wire before it connects to the speedometer.

This ground is eventually supposed to ground to G2 and appears to be a ground in the headlight circuit from the High Beam indicator.

Do you think it would be advisable to rewire this light weight wire with some of the original gauge ground wire or is it possibly doing the job as is?

Thanks