Instrument Cluster Lighting Dark

here is the symptoms so far for my 1993 audi 90 cs vin
WAUBK58C7PA257821. my instrument cluster including the backlighting
for the fan, temp, and airflow knobs, defrost and fog buttons are all
dead and dark. however, the lights for the dummy lights all work (i.e.
if i turn my brights on the blue light lights up on the dash.) also,
the license plate lights (both of them) do not work. i replaced those
bulbs thinking they wree burned out and they still do not light up.
are these two problems related? thanks! -jason

They might be related if the wiring in the '93 resembles the T44 series. In that
series it was typical to have the wires break where they enter the trunk hinge
which caused many problems including license lights and dash lights. I have no
idea if the '93 has the same issues.

wrote:
> here is the symptoms so far for my 1993 audi 90 cs vin
> WAUBK58C7PA257821. my instrument cluster including the backlighting
> for the fan, temp, and airflow knobs, defrost and fog buttons are all
> dead and dark. however, the lights for the dummy lights all work (i.e.
> if i turn my brights on the blue light lights up on the dash.) also,
> the license plate lights (both of them) do not work. i replaced those
> bulbs thinking they wree burned out and they still do not light up.
> are these two problems related? thanks! -jason
>

Jason,
The dash lights in the Type 44's (100/200/5000/V8) are affected by the
condition of the license plate lights, so I would say that chances are that
the 90 is the same. Check for voltage at the license plate light sockets -
if there's none, or intermittent, check the wiring harness where it flexes -
chances are you have some broken wires there that need splicing. Make sure
that the license plate light bulbs are the correct wattage too, I had one
that was a higher (or lower, not sure) wattage and you could see it glowing
faintly when the car was running but the lights were off. Another thing
that I did that seemed to have a good result was to replace all of the
burned out light bulbs in the instrument cluster - you'd be surprised how
many can go and you can still see the gauges. The Instrument Light booster
is controlled by the dimmer switch, I guess when there is a change in the
resistance or current experienced by the booster, or the circuit feeding the
booster (that has the LP lights on as well), then the booster will not send
power to the instrument lights. If all this fails, the Type 44 instrument
lights are also rendered inoperative by a melting of the light switch
stalk - the use of flash-to-pass and the large headlight current passing
through simple plastic and metal switches melts the plastic and causes
instrument lighting to go. Relaying the headlights to feed power directly
from the alternator seems to way to go
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)

> wrote in message
oups.com...
> here is the symptoms so far for my 1993 audi 90 cs vin
> WAUBK58C7PA257821. my instrument cluster including the backlighting
> for the fan, temp, and airflow knobs, defrost and fog buttons are all
> dead and dark. however, the lights for the dummy lights all work (i.e.
> if i turn my brights on the blue light lights up on the dash.) also,
> the license plate lights (both of them) do not work. i replaced those
> bulbs thinking they wree burned out and they still do not light up.
> are these two problems related? thanks! -jason
>

thanks for your help. i'll check the trunk wiring. -jason