[V6-12v] Rear Defogger Switch - 90 v. A6

Eric Ragot eragot at earthlink.net
Sat Oct 8 15:32:06 EDT 2005

Thanks for the information. On an Audiworld post, someone checked the 
100/A6 wiring diagram and there is no mention of pin 4. I guess I'll just 
use it for a while and see.
Too bad you're in St. Louis. My 94 90s is now up for sale...

At 02:36 PM 10/8/2005, Tom Christiansen wrote:
>DUH... You're absolutely right. Pin 3 of the switch is for the heated 
>mirrors. Pin 6 is for the rear defroster. Apparently, there is a 10A fuse 
>inside the switch for the mirror heaters.
>Now that I'm at it: Pin 1: Instrument illumination. Pin 2: Ground. Pin 5: 
>+12 V from the load reduction relay.
>BTW: I saw a bulb replacement procedure somewhere. Probably on 
>www.12v.org. Unfortunately, the site seems to be down (happens every now 
>and then unfortunately). It could also have been at SJM AutoTechnik 
>At 11:16 AM 10/8/2005, Eric Ragot wrote:
>>Tom, doesn't the 90 also have heated mirrors? I Could have sworn I was 
>>able to defrost them...
>>Tom Christiansen wrote:
>>>I checked the wiring diagram for my 1994 90 and you're right. The 
>>>defogger switch pin 4 is indeed not connected...
>>>Wonder if it could be the heated mirrors on the A6 that takes the extra pin.
>>>At 09:48 AM 10/8/2005, Eric Ragot wrote:
>>>>two cars of mine - 94 90s & 96 A6.
>>>>the light on the 96 defogger switch does not come on when it is depressed.
>>>>the 94 switch works.
>>>>I pulled them out and compared - each switch has 6 pin outs. The A6 uses
>>>>all 6 while the 90's switch leaves pin #4 empty.
>>>>Does anyone know what the heck pin #4 is used for on the A6 and if I risk
>>>>anything by using a switch that doesn't have that connector?

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