mchenpa

1992 A4 Coupe FX3 w/41K miles

Help please! I thought this was an easy one; swap the fuse and move on.

Have had the car a month and the driver’s side dash (not cluster behind the plastic) has not worked. I assumed it was a fuse and figured it was position 6. 6 was fine so I thought position 18 maybe; eventually I confirmed all the fuses with a volt meter.

I can understand the cluster being independent and I can even understand the LCD and indicator buttons on the radio and climate control getting power from the units themselves. What I can not understand is how lights in the center console and passenger door work while the ones on the driver’s side dash and driver’s door do not.

No indication of any other electrical issues; interior lights, head lamps, vanity mirrors, outside mirrors, all marker lights, locks, windows, seat, horn, antenna work fine. Car has a new battery and alternator.

What is not illuminating?
• Nothing on the drivers door (I don’t know what should as the car is new to me)
• Headlamp switch/dimmer
• Fog light switch/button
• Traction Control (ASR?) switch/button
• Driver’s information buttons (English/Metric, Fuel, etc…)
• Climate control (backlight only)
• Radio (backlight only)

What is illuminating?
• LCD for digital speedometer and drivers information
• Tachometer
• Gauges
• Cluster warning lights
• Center warning lights
• Green selector lights for climate control and radio
• LCD for climate control and radio
• AT back lighting
• Ride Control back lighting
• Driver’s power seat back lighting (passenger is manual)
• Passenger’s door
• Passenger’s window switch

NTL1991

Not sure if you've figured it out yet, but it looks like you have a bad ground. One ground (G202) grounds all of the bulbs that are working for you, including the AT backlight, seat switch, ride control, and window switch.

There's another ground, G201, which grounds the bulbs for Radio Illumination, Climate Control Illumination, Driver Information Center, Power Mirror Switch, Headlamp Switch, Driver's Mirror Switch and Driver's Door Courtesy Lamp.

All of these bulbs converge into one splice, S203, and then terminate at ground, G201.

Check that G201 is connected securely to a grounded, unpainted metal surface. G201 is located below the Left-hand side of the instrument panel.

Here's the wiring diagrams for the Interior Lights Dimming Circuits:







Nick

mchenpa

WOW!

So, that explains everything and it should just be a matter of finding that ground. It makes even more sense after I noticed that the radio and H/AC do illuminate a little when the dimmer is all the way up and it is very very dark, like in my garage w/parking lights only.

Thanks for the reply. Where did the diagrams come from - shop manual?

I will try to get to it this weekend and PM you with the results ... or maybe more questions.

Thanks again!!

ghlkal

Nick, I love to see detailed and helpful posts like this! Good work, man.

AaronDoud

Can anyone tell me where g201 is?