Rear brake light/turn signal fault

A6 All/ S6 All
#1

I’ve been getting a sporadic fault from the right rear brake light & turn signal. It usually happens after a tropical rain. Tested the bulbs and they are still working—everything is fine the next morning.

Any suggestions?

Here is the scan from Carista:

Body/convenience system:
02743 - Right brake / turn signal lamp

Heater & air conditioning:
00797 - Sunlight Photo Sensor (G107)

Engine:
P1923 - Please Check DTC Memory of ECU Number 2

Engine (2):
P1573 - Left Eng. Mount Solenoid Valve, Open circuit

Radio:
00532 - Supply Voltage B+
00446 - Function Limitation due to Under-Voltage

#2

I had exactly the same problem. Brake light/signal fault, but intermittent, seemed like it happened more often when the temperature outside was low (or high, I forget which).

On the taillight housing, there’s a plastic post with a metal wire terminal poking out the end - it makes contact against another metal piece when you put the housing back in the car. The plastic post that hold the wire is flimsy and breaks somewhat easily, and when it does, it causes that contact point to fail intermittently (or completely).

I pulled my taillight housing, found the pieces of the plastic post that broke off, and superglued them back in place - seems to have solved it.

#3

Mine seemed just fine.

https://uploads.tapatalk-cdn.com/20171202/a1152b58bdab4bd18b9ee709752d6826.jpg

But there is a crack in the housing where the bulb goes in. It looks like it is the backside of a pc board. Is that a sign of concern?

#4

When I had that fault it was something about the connections between the wires and the board… I ended up buying an entire new taillight on ebay or something I think…

#5

If your board is cracked, it’s safe to say you found your problem.

#6

The PC board is fine (in white). The crack is in the housing that supports the PC board. But the odd metallic coloring and texture throws me off. I really don’t know why it looks like that.

#7

The metallic color is probably just overspray from the silver reflective paint inside the housing.

You might also try scraping the contacts on the posts with a blade, if they’re oxidized it might cause a poor connection

#8

you said its after a rain. It might be the condensation. Put some electronic grease on the connections.