Dads928

I took out my pod because I had several bulbs out and the cluster was hard to read. Decided to replace everything with LEDs. All went fine thanks to the great write ups by our forum members. Would have hated to try that with just the WSM. Anyway all back together, contacts all clean, bulbs all tested in place and working. Fired up the car, dash looks great but... No warning light check. None of my over/under limit warning lights work and none of the warning lamps show up during bulb check. High beam indicator doesnt light at all but it did test fine on the bench. I have a slightly suspect headlight switch. When I took the pod switches out, it was starting to separate and was a bit wonky when rotating. was working however and so were my warning lights, high beam etc. All except the burned out bulbs but that was just the backlighting. I compressed the switch barrels halves back together and glued it because the plastic holding clip was broken. I did not dissemble it because ti was working, just coming apart. Action feels great with positive click stops, thought I saved a future repair. When i reassembled everything, the headlights didn't operate at all, only the fog lamps. Dash lighting dims correctly when rotating the switch. Gave up and took a break. Next day, headlights now operate properly, go figure. Fog light dash indicator doesn't operate with the fog switch but comes on the the headlight switch is on and turns off when in full headlights mode. Fogs turn on and off correctly. Everything else functions as it should. Digital dash operates properly and all functions on it are working. So I have no warning lights, no high beam indicator although the lights work, fog light dash indicator operates incorrectly, fog light pod switch illuminates and dims properly.
Anybody think they can point me in the right direction to figure this out. I suspect the headlight switch is still somewhat compromised. The illumination in the switch doesn't work, all my other pod switches light up fine.
There is one other clue but it may be a red herring. Ever since I've owned the car, its had an issue where if I hit a really sharp road bump, enough that you worry about a rim, those kind, id lose the dash completely. LCD would scramble and freeze up all garbled, gauges would go dead all except oil pressure oddly enough. After a period of powering down the gauge cluster would resume normally on restart. This went on for years but very infrequently and went away last year on its own. Haven't had it happen in over a year and I've hit some serious road seams and potholes since then.
I figured whatever was the problem would probably be fixed permanently by removing and replacing the pod as I cleaned and re-seated all the connectors. Thats a different issue because my warning lights have always worked fine except of course when the cluster died but I suspect they are unrelated. It seems I have recreated the problem as my first test drive after the pod lighting replacement produced a road seam bump sufficient to disturb the cluster again. Same thing, let it rest, restart, all fine except I notice that my voltage gauge is reading low and the temp gauge is a bit intermittent. I have a digital voltmeter in my centre console so I know the power system is fine. @13.4 v so all good there. I hit the dash pod hard with the back of my fist to simulate a shock and lost the dash again.!! That only worked once but hitting the dash pod does move the voltmeter back higher a bit and brings the temp gauge back up to where it should be.
I need a place to start looking and testing. There has to be a clue I'm missing in here somewhere and I was hoping someone would spot what I've missed. All connectors are clean and solidly seated. Is it possible this is created by a bad headlight switch or a bad ignition switch? they are both in the pod so could be affected by shock but it seems to me unlikely. Ive got a pretty good handle on how this car all works now after all the years of chasing electrical gremlins but this one is way beyond my pay grade..

Thanks guys
89 s4 by the way

Shark2626

You could take that switch that you described as suspect, remove it from the pod and gently manipulate it, or gently bang it, to see what happens.

It certainly does seem that some connection is loose somewhere. Which in a way is good, it should be easy to find as you move from one possible connection to another. The glue thing though, not sure about that.

Dads928

I had to glue it so it didn't just come apart in my hand. I can buy a new switch which I may do. My thought for troubleshooting was to remove the pod again, pull the cluster and set it on the steering column and hook everything up without he pod shell in the way. That way I can wiggle, manipulate and move stuff around and see about recreating the cluster failure. But what I don't know id where to look for the source of the warning light failure. I believe they are likely separate issues ,

Shark2626

Just throwing this out there... Probably completely unrelated but I suppose it’s worth one minute to check, there is a fuse for the warning lights and the instruments. Might be loose?

ETA. Definitely not related to the “bang” test results you got from the pod, but I don’t really understand all of the issues, that was a long post. A little confusing for me to read. Can you break down the issues in a more concise way? I thought the warning lights resolved with the bang along with all other pod related issues.

Dads928

sorry for the long post I believe they are entirely separate issues. Warning lights don't work and haven't been affected by the impact vibration. The warning lights not working seems to be related to the upgrading of the cluster to LEDs job. The other problem has always been there.
I did check the fuses. Im guessing this is a loose connection behind the pod or something intermittently shorting , again behind the pod. Im just wondering where to look. Harness to the ignition switch, headlight switch or the plug connectors on the back of the cluster or something else I've missed. I maybe should have separated the issues better.