bigredvalve

I have the same problem as many other posters out there. My reverse lights do not (usually) work (although they did for a minute today). I do NOT have any mirror dipping issues. The in-dash gear indicator shows all gear positions lit up no matter what gear I am in. (Unfortunately, I don't know if this is new. The car has some dash light issues thanks to the former owner. Not sure if it was like that back when the reverse lights worked. Sorry.) The rear diff. green indicator light no longer comes on.(does this mean Q is no longer engaging?) But I'm not sure if that change happened coincidentally to the reverse light prob. as it's been summer and I haven't used it. I checked the wire bundles at the hatchback lid hinges...they seem ok.
I've read soooo much conflicting info on this. Some say it's an expensive part. My search for this part for my car came up with this: Can anyone confirm or deny that this is correct? The big question is...where is this thing located? If anyone had a picture, that would be AMAZINGLY HELPFUL. Please, only respond to this if you ACTUALLY know what you're talking about. First hand information, please. Thank you very much.

bigredvalve

Next day....after poking around, I seem to have made things worse. Now the car won't come out of 2nd gear. Can't get above 45mph. Also, where I used to be able to back out of the driveway and sort of glide back while shifting into D for a smooth transition, the transmission now hits D with sudden force, stopping the cars roll back very abruptly... Any ideas? The Multi-function switch? Thanks.

audiqv8

If the backup lights are iffy working only sometimes, then the problem is the multi function switch. The switch is located on the driverside of the transmission which can only be accessed from below. Helped my brother with his A6 Quattro wagon after he tried taking it to a couple of shops. Took three hours to remove and replace it.

"The in-dash gear indicator shows all gear positions lit up no matter what gear I am in." This is refer to as limp mode. You could try removing the battery for about 20 minutes, if you don't have a VAG reader, to clear any DTC codes which is causing your trans to go into limp mode.

bigredvalve

Thanks Audiqv8,
Yeah, I figured out the Limp mode thing. And the battery disconnect trick worked to get the trans back to good order. I got my hands on a wiring diagram which also shows a relay between power source and MFS...I have a mechanic that specializes in that sort of thing who will troubleshoot a good diagnosis b4 I invest the time and money in a MFS. I also found a great post (on this forum, I think) that has step by step pictures and reccomendations from someone who did theirs. The first thing I'm gonna check is for corrosion in the wire harness where the MFS plugs into the rest of tthe system. The boot had slipped down, exposing the connection to all the elements. I might get lucky just by cleaning that up. I'm not sure if it's related, but I no longer get a green indicator light when I switch on the rear differential. I wonder if it's just the light, or if I've lost my Quattro drive as well. Hard to tell on something I only use in the winter. Anyway, thanks for the response. I'll post the outcome for the others out there with similar issues. Oh, anBTW for everyone...The "back up light switch" that I was searching for doersn't exist on my car, because it's only in Manual Trans Audis. The MFS handles it all in the Auto models. The parts sites don't specify trans type.