B7 S4 Electrical Problem: ANY IDEAS????? [Archive] - Audi Forums

: B7 S4 Electrical Problem: ANY IDEAS?????

02-21-2011, 08:11 PM
I have a 2005 B7 S4, recently it started having electrical problems. Not sure if they are connected, but it first began after I left it outside one rainy night, when usually it's garaged. Anyhow, went out in the morning and noticed the rear tail lights were illuminated but dim. Car started so I drove it home. The next day I came out and the battery was dead. Guys at my parking garage said the alarm had been going off all night...which never happened before and I assume is connected with my problem. Jump started it and took it to my garage. he's not an audi certified or audi dealership...but always does good honest work on my cars. Anyhow, left it there overnight and the next morning car was fine. Figures right? :confused: So I picked it up and it was fine for about a month. Couple of weeks ago I came out and noticed the front driving light bulbs and the yellow lamps on the side of the headlight housing....all dimly illuminated. The rear brake lights were also illuminated. Damm. Well the car started at least. The other day....you guessed it....came out and car battery was dead. So I took it to Audi and they said they will hook it up to the computer to diagnose the problem. They said it was probably the rear brake light switch or maybe a short in the alarm module...most likely. They charge $160/hr (ouch!) and said most likely they can find it in that first hour. After that, it's probably a $30 part. This was speculative, but a mechanic was there and agreed it could be that simple.

***One thing to note....on the bottom of my coolant tank there is a small hole and coolant is leaking very slowly from that. I plan to replace it soon...but do you think that could be related? Is there some wiring or module below that which could be tweaked as a result?***

Has anyone had a similar problem? Any ideas? I have a funny feeling I'm not getting out of that Audi dealership for $200...lol....afraid of a "we just can't find it" situation.



02-22-2011, 07:07 PM
Hi! There is not that much electrics below the tank, but it has to be fixed 100%. As for the electrics - Google for Audi drainage system (sun roof and below the windshield), clean it, then get locations of relay panels (behind the steering, under the hood on the right, passenger side). You would need to check it all - there might be water and some bad contacts.

02-24-2011, 12:04 PM
thanks for the tips.....I will definitely have to look into the channels!!!