s3trios

For all those that have suffered getting water into their A8 tail lights and the water corroding and destroying everything inside.

Once the electronics start to corrode/rust there's really no other choice but to replace it with a new one. Quite costly if you ask me, even 1 tail light costs at the very least $200 from the junkyards or ebay (yes I checked).

I've had my 04 A8 for about a year and the tail-light on the trunk (passenger side) has always seem wet after it rains. I ignored it for a while thinking it was just condensation until the light gave out completely.

Here's the tail-light with water in it.



The voltage controller board for the LEDs has died, a lot of rust and corrosion. The board is actually made by Tyco. The 2 black wires coming out of the board are the + and - leads to the LEDs.


Here is the LED board. Surprisingly, most of the LEDs still work, only a couple are dead. I cut off the leads to the board and tested the LEDs with a 9v battery and they lit up.


So for the fix, basically the LEDs still work but will need switched power. I figured the easiest way would be to tap into the driver side tail-light and wire them together.


I soldered the + and - wires to a new wire and ran them out the rubber grommet.


The latter part of the night was spent taking the other tail-lamp out and splicing a wire to the same + and - leads on the LED board. I re-installed everything and now both sides light up. Be sure to use some extra silicone or other sealant to seal up the grommets and rubber gaskets on the tail-lights. That's how the water came in, the rubber gasket was old and brittle.

Also, I am fairly certain the LEDs on all the tail-lights *can* be un-soldered and replaced individually if they go out.

MP4.2+6.0

I like it!

mishar

So much that you would do it to your W12?

Galco

Turn signals working OK?

s4master1

so you telling us the engineers went to all the hassle to install a circuit board for nothing when all you need is a power source???
the circuit board is there to reroute power when a bulb fails like a parking light or signal light.
when a bulb fails the computer closes that circuit and routes it to the leds, the board recognizes the voltage change like when brakes are applied and regulates the brightness of the leds, as per AUDI.
never actually seen it work on an A8 but a lot on A6 as the tail lights fail a lot as well the q7.
most manufacturers use this system now and works great.
many times customers complaint of a light in the cluster is out and never find an actual light out in the exterior of the car, due to the computer routing the circuit.

s3trios

That's great and all, but it remedies my problem. So now I have 1 board running 2 LED boards. The brakes and turn signals work as well.

mcdream

Yup, that's possible. I had pre-facelift taillights before I switched them to facelift ones... On one of those lights I swapped out all the leds, quite an easy job for someone who knows how to work with led lights. I had it done by a friend. One you start to replace them, it's very hard to find the right color... especially with the amber turning lights... in the end I chose to replace all of them so they would look the same. Also in that case all leds were new and no problems later on with older leds starting to die...
Since I opened up the lights for the same reason (moisture inside), I dried them, had some corrosion protection put on the circuit board and resealed them with silicone to be sure. It's also a good idea to wax the lights as there might be some micro cracks there...
In the end brake lights looked the same but with turning lights, there was a very mild color difference with the other side (untouched original color) but it was something that you really had to look for...
In the end it cost me like 25€ (1 hour of work + leds) or so, which is about 10x less than a new light.

Mister Bally

+1

My '04 A8 is the first Audi I've owned where I have NOT had moisture in the Road side tail light assebly that is affixed to the rear quarter panel. Well, so far anyway. The previous ones were remedied by drilling a 1/8" (okay, for S4master1 I'll use engineering units: .125") hole at the lowest point so the water could drain. I had previously tried to siliCONe seal everything but could never find a water entry point. It looked like an aquarium. Once the water level hit the lowest light bulb, it would crack the bulb and of course, cause the filament to break.

transporter2004

I currently have water in both taillights located on the deck lid.
I am very hesitant to take them off the car an try to epoxy them or seal them with silicon. I don't want to booger it all up. I just try to not open the trunk, but I know that the water is reeking havoc on the boards.

Has anyone ever taken the light off the car, popped off the lenses and "glued" it back on with any success?

Has anyone just bit the bullet and bought the 05 or 06 aftermarket lights for sale on the internet for about $1700? were they plug and play?

thank you

s3trios

Well if the lights are still working meaning your reverse, rear fog, and LED brake lights.

You can still save the trunk lights by fixing them yourself and not have to go thru what I did and by fixing meaning removing the lights and using a hair dryer to air them out and resealing them.

Go buy yourself 2 fresh rubber gaskets for the lights and a tube of silicone sealent. Once you get all the water out and cleaned up any other rust stain or whatever, install the new gasket and seal the enclosure up with silicone sealant. Do not use epoxy.

Also, the trunk liner comes off easy. 1 screw under the emergency trunk handle, 2 screws in the black plastic cup next to it. Remove your emergency tool kit and pop the liner off. It's all held together with metal tabs. 3 8mm nuts on each light, unplug the connector and slide out. Use windex to get the rubber grommet back when re-installing.

I rather burn 1700 dollars on something else