Relay board ??'s.....engine compartment

[John2kx]

Bare with my nomenclature here........I'm new to the 914 arena and have a few questions about my '73.

First of all, ALL the electrical components of my car work. I pulled the engine a few weeks ago and am getting ready for the replacement. When pulling the cover off the relay board (located in engine compartment) I noticed that some wires have been spliced from the forward multipin connector to the rear 14 pin connector.

From my labeling of wires from the rear 14 pin connector during engine removal, I have found the following wires from the forward multipin connector were jumpered to the rear 14 pin connector:

(-) side of coil and
wire to starter solinoid

I have considered leaving it as is since everything works but bypassing relays, fuses or the like just bug me. Do you think that something is wrong with the relay board itself and the jumpering between connectors was used to correct this? I flipped the board over and see many hair line cracks and a 1/2" x 3" area of the epoxy type material missing, exposing some internal metal (copper colored).

I've seen these relay boards for sale pretty cheap on ebay. Would you consider replacing with another 30 year old part?

Are they available new?

One other thing......my car no long has fuel injection and I assume some of the open plugs on the relay board once were plugged in to some of the injection system.

Any help in this area would be appreciated.

John "electrically challenged" T.

[rich]

I think you are right about the wire jumping. I would say your right about the bad relay board as well. These do fail. Check to see how many circuts you are actually using, then decide if you really need the thing or if you could just install a new connector and form a plug-in for the rear wiring.

Good Luck

[SummerSledSix]

John in addition to providing a relatively sheltered home for the relays, the relay board also jumpers some circuits from the 12 pin harness to the 14 pin harness. Porsche probably did this to make the harnesses easier to manufacture, install, and replace if necessary.

The two circuits you mentioned, the starter wires (yellow in both harnesses), and coil (black / violet in both harnesses) are actually jumpered to each other by the relay board. Your external jumpers are most likely there to either fix a problem with the board, or to restore an earlier modification back to original configuration, perhaps a CD ignition system. In any case, don't remove the jumpers unless you plan to replace the relay board. You can get a new one from Pelican, among others, but they ain't cheap - about $300. Those jumpers don't look so bad after all, do they? Used e-Bay specimens are a crap shoot; do you feel lucky today? Better to be able to eyeball one at a swap meet (ie Hershey, next month).

The fuel injectors used to hook up to the 4 spade lugs poking up near the 12 pin connector. All this and more information can be yours for the price of a Haynes manual, tho you need to drink a litre of German beer before you can decode the electrical diagrams back there!

The missing epoxy stuff is interesting, does it look like someone physically removed it, or that it flaked off due to age? Hairline cracks in the epoxy are fixable, but if the metal "tracks" are cut, cracked, or corroded thru, then you've got your reason for the jumpers. You can fix cracks in the traces with solder, but jumpers are probably easier than the prep for a good solder joint.

If you feel game, clean the back of the board as best you can with solvent and a cloth, let it dry, then give it a light coat of clear polyurethane. That will reseal the little metal traces from the elements and prevent more corrosion. Be careful not to get any poly on the connector contacts on the other side!

Good luck.

[John2kx]

Thanks for responding guys. I didn't go into detail with what this project really consists of. I'm stuffing a Renegade v8 conversion in this one and not really wanting to just restore my wiring to stock configuration.

Your right.........I didn't want to roll dice on a 30 year old used board and almost ordered a new one from Pelican today. I decided to make a phone call to Renegade first since they are providing a harness which is mounted to engine (dist., coil, starter, alternator along with other engine monitor devices).
The idea here is to connect their harness to all accessories on engine while on the engine stand, lift engine into place and then plug into relay board. I failed to recognize their harness bypasses the relay board altogether by plugging into the 12 pin (forward) connector.

This should solve all my potential problems.

One thing is not adding up though. The yellow wire (starter) from the forward connector that is jumpered to the yellow wire on rear 14 pin connector does not appear to have a connection point at the forward connector. In other words, I see no place to splice back in to. The coil wire (black/purple) is spliced and there is a stub out of same color wire coming from forward connector. Wonder if the previous owner just yanked the yellow wire out of the forward connector.

The yellow wire is really large compared to the others stuffed into the forward connector. Does this wire (yellow) wire actually connect to the forward connector? Or does it go to the starter direct?

A couple of beers didn't do it for me when trying to figure out the wiring diagrams I've seen. I'll try doubling the dose tonight and see what happens : )

Thanks again all for your help..........this board is great!!

[SummerSledSix]

John,
The yellow wire on the "forward", or 14 pin connector should go directly to the ignition switch. The yellow wire on the 12 pin connector is the one that heads off to the starter solenoid itself.

This brings up another reason jumpers are present - somewhere during the life of the car, something shorted out. If so, the circuitry on the relay board is usually the first to "toast", since the printed circuitry is generally thinner than the wire that connects to it. In other settings, this arrangement is known as a fuse. Pin 1 on the 14 pin connector (at the corner of the board) is where the yellow wire that runs up to the ignition switch should be. Is the harness jacket taped? Chances are the original yellow wire might have been fried, and somebody replaced it with whatever color they had available. The harness on my car has at least one replaced wire in it, after un-taping the harness, I found what was left of the original wire's insulation melted to other wires around it. Not that I'm a harness voyeur or anything like that, I had to figure out how to splice in the engine harness for a Motronic based six cyl. A short in the (high current) starter solenoid circuit might also explain the missing epoxy on the relay board; anything look charred to you on that board?

If you're putting a V8 in there with its own alternator and fuel system, the relay board is pretty much useless. The only functions left would be the rear window defogger relay (assuming you have the defogger option), and the heater relay, which probably won't have a header based heater box to blow into. All that's left are the jumpers, and to figure that out, make sure you're drinking *proper* German beer, not some cheap domestic imitation!

[John2kx]

Yellow wire coming from front of car is not fried. Harness is original (no tape) but does have about 3" near the connector missing. I assume this was done to allow enough room to perform the splicing operation.

I've spread the wires at both connectors and see no sign of toasting/damage. The cracks and missing epoxy on bottom of board do not appear to be from any shorting.......really just looks like aging.......the material here is not that thick.

Guess I need to figure a way to get that yellow wire back to the number one pin on the forward connector. I'll dig into that more tomorrow.

Can the connector be opened up? It looks like it may just snap together. I have not tried any force as of yet. If not, it looks like I'll have to find another connector with a minimum of 3" of wiring and do some splicing.

Your right about the v8 conversion stuff. The heater will have its own fan/water supplied heat exchanger installed up front with separate power supply.........a/c installed/powered in a similar fashion. I don't think I have rear window defroster.......doesn't really matter where I live (Ga.) I've never used this on any of my cars supplied with such.

I appreciate your help with this John.

[Dave at Pelican Parts]

The connector does open up by prying. Be careful not to break the plastic, though.

For a color diagram showing the relay board traces (and wire connections for a 73), see: http://www.pelicanparts.com/914/parts/Electrical/914_electric_73E.jpg

--DD

[John2kx]

Thanks Dave!!! Looks like I'm armed with what I need to know to fix this problem in the morning. I'll let you guys know how the connector separation goes tomorrow.

BTW, how do the connector halfs fasten to each other? Any recommendations on how to perform the separation? I assume a thin screw driver or maybe my 1" wide puddy knife slowly working from one point all the way around. Any majic, trible knowledge
would be appreciated.

I'm looking forward to fixing this. My real task tomorrow is to finish paint stripping the engine compartment in prep. for repaint while the engine is out..........sounds like fun, huh?

[SummerSledSix]

Hope you're using a respirator or something when you're sitting crosslegged under the engine well with fumes or dust swirling around you. You may not need those extra lung cells now, but you'll want 'em when your 70 .

If you look at the connector with pins facing you, you'll notice the cap has a barb that catches another barb on the connector body; just separate the barbs with a screwdriver and the top will come off. Be careful, though, the cap is what keeps the pins in the connector - without it, they'll start to back out.

Bless those Porsche engineers (at least the older ones), as funky as those connectors look today, they are *repairable*, not like those molded micro-mini things I need a new pair of glasses just to count the pins! Have fun - got solder?

[SummerSledSix]

Oh yeah, I forgot to mention -
When I was fooling around with my own harness issues, a local Porsche "recycler" gave me a 14 pin connector body with new pins that he "ordered, but never used". Point is, you might be able to get "virgin" repair connectors to mate with your existing 12 or 14 pin harness connectors and make a clean and separable adapter harness to hook into to your V8 guts. Don't know part numbers, maybe Dave's crew might know...

[John2kx]

I took the connector (plugs) apart today on both the 12 and 14 pin connectors. They came apart with ease using a medium size flat screwdriver. The forward connector (12 pin) has at least one (maybe two) of the pins missing inside the connector. Not sure if this is per design or the reason I can't determine where the yellow (starter) wire is supposed to land. There is not a pin within this connector that does not have a wire landed......none of them being yellow.

Looked at the diagram that Dave sent but could not determine which pin the yellow wire should land on. Is there a diagram out there that shows the location of wires/pins for these connectors?

The rear (14 pin) connector was pretty easy to figure out. The yellow wire/connector is still in place and I can see where it was cut in the past to allow for jumpering to the forward connector. I plan to use the remains (pin and 2" of wire) from this connector and installing in the forward connector when I can determine which hole it should land in.

[Dave at Pelican Parts]

A bit backwards there: The front connector is the 14-pin one, the rear is 12-pin. And the diagram clearly shows a yellow wire going to the right-front pin in the 14-pin connector.

--DD

[John2kx]

Had to look at that again Dave before it made sence. Thanks for pointing it out.

Now I'm clear on how to return to normal!!!!!!