93_Audi_90CS

Can my trunk harness affect my fog lights? Turned them off (they have been on for a while now) and when I tried to turn them back on, the switch does nothing (same for the rear light). My trunk harness has been messing up my central locking and I am wondering if now it is messing up my fog lights....

93_Audi_90CS

OK...after searching through some older posts...looks like it could be a couple of things affecting my fogs. Either the relay is blown (seems to be the best explanation for the prob as both rear and fronts stopped working at the same time (as well as their associated dash lights)...the wiring harness in the trunk...or the switches. The switches seems a bit far off for me as they both went at the same time...would have to be a hell of a coincidence.

If I disconnect the trunk harness...would that prove that it is or is not the problem?

dnachristen

It could be the switch. I think one switch feeds the other if I'm right.

None of mine work right now, but the relay is good. Opened it up and tested it with 12v. Fuse is good... Did you test your fuse?

93_Audi_90CS

OK...now it has gotten interesting! Was on my way home to troubleshoot when all my gauges stopped working. No speedo, tach, gas or temp working. The acceleration felt weird as well. A little sluggish off the line. Stopped at a local auto parts/repair shop and checked under the hood for fuse/relay out of sorts. Decided to try and limp it home and it wouldn't start. Turn the key and nothing....a faint click...likely the relay I heard, but no starting. So the symptoms started like this...

1. Central locking started to go weird...likely cause is the trunk harness.
2. 2 weeks later the fog lights go...think it's the relay as both went at same time.
3. All dash Gauges (and seat warmers) stop working.
4. Car won't turn over...and I did try and boost it. Tested battery and all is good there.

So now I am car-less and 50 miles from my car. Need to sort it out ASAP as it is at a less than reputable repair facility. (Canadian Tire for all you Canucks out there in Audi land...so you know I want to get it out of there as fast as I can.)

Right now I am ready to break the bank and take it to an Audi dealer. I am pretty handy but I think this one has me by the *****. Could it be the harness in the back that is causing all this? Bad Ground??? I am at it's mercy!

dnachristen

Sounds like a bad ground, or the fusible link is gone (or bad connection) as far as the no start condition.

Check the main lead off the battery that goes to the fuse box. (+) If you lost cabin power start from the main source and work backwards.

93_Audi_90CS

I got the car to an experienced German car guy and he is giving me a hand to diagnose the issues.

Would the ignition switch be a problem? Relays?

The starter works fine as we can jump the starter and the car starts up. So somewhere between the ignition switch and starter there is a problem.

Fuseable link was mentioned....any idea where it's located?

dnachristen

If you follow the smaller + line off the battery, it'll go into the link. But if the car runs when the starter is jumped, I would say the ignition switch is bad. The switch feeds power to accessories and such. If it progressively got worse I say you found your culprit. Don't cheap out and get the inexpensive switch or you'll be replacing it again in less then a year. Go for the good German one.

On a side note, since my fogs have never worked (only had the car 4 months) Where is the rear fog light located? I know, silly question. How bright is it?

93_Audi_90CS

To update...there were 2 blown fuses that I found. I replaced them and after a little while they blew again. After searching the forums, I think my sketchy trunk harness is shorting out and blowing the fuses. Time to replace it and go from there. If that fails then the ignition switch is next.

Rear fog light is locate in the trunk section (flip up part)on the drivers side. Should notice a rectangular section that looks like it should light up. Remove the trunk liner (a few screws I think) and you should see the bulb holder assembly.

I will be picking up a harness from a local wrecker and I will see if that does the trick. Other option is to cut and splice new wires in...which is my least favorite option.

dnachristen

The cut and slice method is going to be the best method. If you get a harness from a wrecking yard it could have the same issue.

By re-doing the wires you can put a little strain relief in so it doesn't happen again.

Thanks for the tip on the fog light...lol I'm such a noob.

greasegun

hi
can tell me what fuse did you replace?my 1998 cabriolet engine won't turn not even a click. i replaced ignition switch but still the same.

thanks
greasegun