1996 A6 dash panel problems

[C3B4C4]

Hi,

I've had my 'new' Audi A6 2.3 for a few weeks now, but today I have a really odd problem with it which I thought I'd mention to see if anyone can suggest possible solutions.

Car details: 1996 (registered) A6 2.3 auto, MY95, NZ new, about 200 000km.  The car has a speedo, rev counter, fuel and water temp gauges, digital odometer and trip meter, trip computer and auto check, along with auto trans indicator, voltmeter, analogue clock and oil temp gauge.  I'm guessing this is a fairly common instrument layout.

After being out earlier in the day I came back to the car to find I'd left the side lights on.  They'd only been on for an hour when I got back to the car and, first pop, the engine started without any hesitation.  What I also found was the rev counter and odometer/trip meter, clock, fuel and water temp gauges not going when I started the car.  Moving the car forwards the speedo also wasn't going.  The only things working on the dash are the individual warning lights, the oil temp gauge, the voltmeter (which shows normal charge) and the auto trans indicator.  The backlights for the digital displays (odometer and trip computer) still work too, because you can see them dim when you turn on the exterior lights.  It's really confused me.

Any suggestions on where to start looking?  The fact that the dash panel still has power to it makes me question if it's something in the speed sensor side of things.  All fuses are ok.  Worst case it's an all new dash panel which I guess would be from a wrecker somewhere!

Cheers,

Paul.

[typ53]

How'd you get on with your dash?  Did you get it sorted?

[C3B4C4]

Ended up being a fairly simple fix (for an auto electrician).  A faulty capacitor was interrupting the dash panel power supply.  Once that was fixed everything was fine.

[typ53]

Good to hear.  Hope it wasn't too expensive.

[BB]

Most of the modern dashes run on a reduced voltage say 10 or 7v so that they can supply a smoothed out voltage that dosen't fluctuate with the alternator, load etc
 these can cause faults such as all the gauges pegging out at the top (dash getting full voltage) to nothing. its a small three legged beast screwed into the back of the dash on simple cars like the old mk1 and 2s and all the early Audis etc.

[qta4]

Its called a three terminal voltage regulator Jeremy. 12 volts in ,an earth terminal, and regulated 5volts out..

[BB]

Yes that's his name.