[V8] Automatic Transmission Multi-Function Switch

Kent McLean kentmclean at comcast.net
Wed Apr 29 13:21:21 PDT 2009

Tony wrote:
> You can actually remove the switch enterely, and simply jump the wires 
> needed. I'd just cut the plug off, and solder or crimp and heat shrink 
> the needed wires. Actually, I'd fix the starter issue by jumpering the 
> relay, but here's what you need to know for the switch.
> As mentioned, you need to find the blue wire for the reverse lights, and 
> provide 12V+ to it. 

Success!  So far.  I pulled apart the MFS harness and found the blue wire.
I put 12V to it, and with the car running the backup lights came on. You
wouldn't believe how excited I was to see those lights on.

Updated details and pictures here:

I still have to actually run the wires from the backup switch on the
transmission to 12V and the blue wire, but the difficult part of the
puzzle is solved.  And I need to dig deeper into the harness to find
the wires for the start relay (or jumper the starter relay itself).

Thanks to everyone for their help and insight.

Kent McLean
1999 A4 Avant, V6 Tiptronic
1991 200 TQA #3, with mods
1990 V8 w/5-speed and other mods
gone: '91 200 TQA x2, '94 100 S Avant, '89 200 TQ "Bad Puppy"

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