A8 / S8 (D2 Platform) Discussion Discussion forum for the D2 Audi A8 and S8 produced from 1994-2002

Brake light problems

 
Old 12-17-2003, 01:33 PM
  #11  
AudiWorld Member
Thread Starter
 
cpbetts's Avatar
 
Join Date: Dec 2003
Posts: 111
Default Re: Brake light problems

Hi there,

The car is a 1999 model 4.2 quattro. You guys sounds as though you know whats going on, and please forgive my ignorance, but could you tell me where to located the connections which are suspected badly grounded. I'm still new to the car (and apart from relacing a bad aerial mast) haven't done anything else on it), I bought it only 4 months ago.

Thanks again for all your help.

chris
cpbetts is offline  
Old 12-17-2003, 03:57 PM
  #12  
Junior Member
 
Join Date: Oct 2000
Posts: 950
Default The bulb or socket could also cause a bad tail/brakelight ground

... if that is the problem.

Tom
ttuling is offline  
Old 12-18-2003, 11:46 PM
  #13  
Junior Member
 
Join Date: Oct 2000
Posts: 950
Default Ground locations, and how to choose among them

Hi Chris,

We have discussed two kinds of ground connections: (1) wires attached to each other within a wiring harness, which lead to (2) electrical terminals bolted to the chassis.

I don't know where the in-harness connections are -- the service manual specifies only which harness, for example B108 is "in wiring harness interior, right, rear".

The chassis attachment points are better known. The "JPG of the TSB" posted by Paul shows how to get to ground point 43.

On a 2001 car at least, ground points 59 and 60 are just in front of the left and right low level brake lights, respectively. You can access them by removing the covers in the trunk as if you were going to change a brake light bulb. Start with the battery compartment cover and its counterpart on the left side, then remove the little access door ahead of each brake light. Each ground terminal (on a 2001 car at least) has a brown wire and is bolted to the chassis ahead of and below the brake light.

If you can catch the car with the high level brake light stuck on, the simplest way to determine which of the three grounds (if any) is at fault could be to leave the headlights on, then (1) move the ground connection wire near one then the other low level brake light while watching the high level brake light, and if that doesn't turn it off, (2) remove one then the other low level brake light bulb. If removing either bulb makes the high level light go out completely, that bulb, socket, or it ground path is at fault. If removing either bulb only dims the high level brake light further, then the B104/43 ground path is probably at fault.

Tom
ttuling is offline  
Old 12-29-2003, 02:00 PM
  #14  
AudiWorld Member
Thread Starter
 
cpbetts's Avatar
 
Join Date: Dec 2003
Posts: 111
Default Re: The bulb or socket could also cause a bad tail/brakelight ground

I checked the cars rear lights over the christmas holidays, and suspected a faulty connection between the brake bulb and the holder.

Whilst removing the bulb i dropped it onto the floot of the boot.... the filiment broke so I replaced it. I don't have the problem anymore so suspect (as mentioned in the subject) that the bulb was at fault.

many thanks for all your help.

chris
cpbetts is offline  
Old 01-02-2004, 09:28 PM
  #15  
Junior Member
 
Join Date: Oct 2000
Posts: 950
Default Very good, thank you for the reply

You probably fixed it permanently, but if not, a bad wiring connection to a bulb socket is likely to blame. You can gain confidence that the bulb was at fault by turning on the headlights and watching the high brake light while manipulating the wires to the bulb you changed.

Tom
ttuling is offline  
Old 09-26-2014, 04:27 PM
  #16  
AudiWorld Newcomer
 
Join Date: Sep 2014
Posts: 3
Default I have a 2003 a6 problem with rear lights staying on at night.

Any ideal where my ground wires are?

When I apply the brake my lights come on.

When I let off they do not stay on...
I have changed bulbs but nothing at all.
cbrady871 is offline  
Old 04-03-2019, 10:30 AM
  #17  
AudiWorld Newcomer
 
Join Date: Feb 2019
Posts: 2
Default

Originally Posted by PaulW View Post
What year car? When you say "high" brake light, do you mean the one in the rear window on the parcel shelf?

It sure sounds like you have a bad ground to me. Will need to know the year though.

pw
I have this problem... The year of mine is 2006 A6 .. I would greatly appreciate it I can get some help.
Valerie Allen is offline  
Old 04-03-2019, 12:22 PM
  #18  
AudiWorld Senior Member
 
Join Date: Oct 2005
Posts: 944
Default

You are posting in the wrong forum but maybe the brake light switch? They get worn and need to be adjusted or replaced on our 1994-2002 Audi A8 and S8 cars.
Careful if it is this switch do not drive the car. The transmission torque converter clutches can get burned out if this switch is not working properly, the transmission declutches a lot thinking you are hitting the brakes.
jfrahm is online now  
Old 04-03-2019, 12:26 PM
  #19  
AudiWorld Senior Member
 
Join Date: Jan 2004
Posts: 633
Default Check the bulbs in the problem lamp

If a double filament bulb has one filament broken, it can lay across the other filament and create a sneak circuit.

Weird things like hit the brakes and it back feeds the running lights and cluster lights because that one double filament bulb serves those two circuits.

Check for: 1) broken filament in double filament bulb creating a cross circuit 2) melted contact **** on the bottom of the bulb also creating a crossed or backfed circuit and 3) check that you didn't put a single filament bulb on a double filament socket...the single contact on the bulb bridges the two contacts in the socket.

My money is on a broken filament, especially if the issue is intermittent.
BrianC72gt is offline  
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
roastbeast
Q7 Discussion
4
09-04-2015 04:22 AM
ECS Tuning-Audi
A4 (B6 Platform) Discussion
0
09-02-2015 11:39 AM
stormchaser1967
Audi A5 / S5 / RS5 Coupe & Cabrio (B8)
0
09-02-2015 09:26 AM
Beena
A4 (B8 Platform) Discussion
0
09-02-2015 12:01 AM
C6Silver
Q7 Discussion
4
09-01-2015 08:46 PM


Thread Tools
Search this Thread
Quick Reply: Brake light problems


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: