nuc

I'm tracking down non-functioning reverse lights. The problem is not a fuse or relay, they have been ruled out. I am not getting 12 V at the relay socket when the tranny is put into reverse (also gear indicator on dash is not working, which is related). Could someone tell me exactly where, under the dash the 2 pin connector is and what it looks like, that sends 12V to the tranny switch which then sends the signal to the dash and reverse lights?

Thanks

jpitman2

Model year?
Transmission???
Make it really hard next time....it is a 928 isnt it? Standard info in your sig is a big help....
jp 83 Euro S AT 48k

nuc

Sorry, it's an '87S4 Auto.

I'm so used to posting on GN boards, where everyone has a GN and there all very similar that I forgot to post info. on the model.

Jim bailey - 928 International

The neutral safety , trans indicator, backup switch is located on the transmission left side where the shift cable attaches. The wires plug into the main harness in the spare wheel well front right corner.

nicobel

good, i have exactly the same problem...!
Go checking

nuc

there are quite a few wires and connections in that area covered by a black plastic cover. Some of that wires look to be fairly heavy duty and thick, while others are of a smaller gauge. Are there pics of that area with the wires labeled for what goes to what?

Thanks for the help

I also have the service manuals, but don't see a pic of that area

nuc

Ok, after some further searching of the message boards and some diagnostics, when turning ign. on and shifter in R, I have no power at terminal 86. Other terminals check out ok with jumping 12vdc to term. 87 giving me reverse lamps.

With ign. on and shifter in R, I have no power at red/black wire in front right of spare tire well.

Where do I go from here?

Thanks

nuc

Cleaned all grounds in spare tire area, switched out relay for known good one, still no reverse lights.

Where does the red/black wire, that goes to the switch on tranny, in the spare tire area, get its power from. I still have no power there when I turn the key on or shift into reverse.

Thanks

BrianG

I have the opposite problem... I get reverse light in park, reverse, 2,1, but not in neutral or D.

The fuse for the backup lights is the same as the fuse for the rear wiper.... does that work?

Marc Schwager

With the caveat that I have never done anything on an S4, I can tell you what it looks like from the wiring diagrams. BTW, if you don't have these, I wouldn't count on being able to keep a 928 running :-)

The connector in the rear should have 2 wires heading into it from the car electrics side:
Pin 3: Blue from pin 87 on the relay - leaves the panel at U21
Pin 4: Black/blue heads off to the lights (looks strapped to pins 1,2 also)

The two wires to the switch are Blue (pin 3) and Brown (pin 4).

Long way of saying, I don't see a red/black wire associated with the switch on the wiring diagrams.
In any case that's all downstream of the problem if you are able to energize them by jumpering 30 and 87. The question is whe pin 86 isn't getting power to trigger the relay.

nuc

Thanks for the info. Marc.

I did not see any wire colors like you specified. I did find the colors which I mentioned earlier, these were from this thread:

https://rennlist.com/forums/showthre...ack#post281853

Looks like I'll be diving into the fuse panel to try and figure out what the problems are. Oh yeah, after the int. lights have been on for a couple minutes, the fuse blows, AND there is a funky-mid 80's alarm system spliced into the box that needs to come out. Looks like it won't be running for a little while.

nuc

Couldn't figure out what the problem was, so I opened up and removed all the old fuses and replaced with new and stabilant coated them. Removed circa 80's alarm system with plenty of splices. Put it all back together:

Reverse lights work
Rear hatch release works
Interior lights work
Cigarette lighter works
Dash gear indicator lights work (D is blown though)
EVERYTHING WORKS!!

BC

Thats what I call a good day.

SharkSkin

Stabilant is great stuff... I coated all of my fuse panel connections with it, and have had no gremlins arise from that area.

nuc

Yeah, it was a nice surprise. The problems weren't making sense. So I started with the basics.

Sharkskin, it was because of your site that I looked into that stuff.
NAPA wanted $60 for 15 ml of the 22A and I couldn't bring myself to spend that much. So I looked on the web and found a place out of new york, posthorn.com that sells stabilant 22 (pure) that can be mixed w/99%isopropyl to make 2 15 ml. amounts for $29 not including shipping.
You may want to look into them when you need more.