Centre brake light and reverse light problem, along with a smashed radiator

[Andygil]

Hi folks how's things?

I've got a 2008 3.0 A4 Quattro automatic and each day is different with it. Some days there's no problems at all. Other days I get in and start it and the warning for my centre brake like comes up on the dash but weirdly sometimes it still works and sometimes it doesn't, when the warning is the on. Then at random times either the left or right reverse light warning comes up, again both are working fine. 

Anyone had this problem?

Off the subject here but I drove over a kerb and broke my front bumper and radiator. Radiator has been replaced already but the problem I'm having is getting the parts from underneath the car that were pushed back and broken. I need a new front bumper and the radiator and bumper supports.

Long winded but any advice is helpful.

Thanks

 

[Magnet]

Hello Andrew,

Re. the problematic rear lights and warnings - check the wiring within the flexible harness which links the body to the boot/tailgate. Not unusual to have cracked/broken wires in there due to years of flexing. Just carefully pull the corrugated rubber cover back and give all the cables a good coat of inspection. 

Re. your bumper. Personally, I would not replace the bumper, if the photo represents the extent of the damage. The basics of this should be repairable by plastic welding, although you might need to replace /fabricate some associated parts.

Kind regards,

Gareth. 

[Andygil]

Thanks for the info Gareth much appreciated. I'll have a look at the wiring tonight. As for the bumper, there is more damage than shown in the pic unfortunately, there are plastics under the rad and supports which have broken. 

Went to a crash repair place in Belfast and he quoted me 1500 🙈🙈🙈

[Liber_A4_te]

All Regarding the Brake light and Reverse light, this will be 2 things, all attributed to a break in signal from the bulb to the ECU.

1) As mentioned, is a break in a wire from the bulb housing connector (least likley) 

2) Corrosion on the terminals or bulb housing. (Probably this)

I had issue number 2 and is easy to diagnose. 

Open the boot and you will see on either side of the inside of the boot lid the 2 squares in the fabric where you gain access to the bulbs. Open this, and pop the bulb housing out of the rear headlight (Disconnect the wiring harness first is a good idea. 

Once removed, looking at the bulb harness (So the bulbs are facing you), you should see a black plastic case with metal tracks running over the housing. These tend to rust up due to the seals in the headlight drying out and letting in moisture, thus corroding anything metal on the housing. If it is this, 3 options

1) (CHEAPEST - Remove bulbs and set to one side, place hole bulb holder in a tub of White Vinegar for 1-2 days, scrubbing with a wire brush or steel wool occasionally untill corrosion removed (This will work for a while, but ultimately the corrosion will come back. 

2) Purchase a new bulb housing from Audi (Or online) and it this. Corrosion gone. problem gone. HOWEVER, unless you sort the reason for the moisture ingress, you will get the issue again. BTW I though Audi would rip me off, but turns out they were the cheapest. Housing only cost around £18 last year, everywhere else on the web wanted £25+

3) Best Option - As above but also remove the rear headlight unit aswell. Remove the dried up seals (Foam like material), rub down lightly and attach brand new seals. Again, Audi were cheapest. Seals were around £8. along with the bulb holder it was £25 all in. and job satisfaction.