mrfixit54

My 1999 A6 Avant third brake light works intermittently. I have seen this work one day, then not another day. I have even seen this work but only glow dimly.
I would like to replace this light assembly but gaining access seems to be difficult to say the least. Can anyone offer strait up advice on how to gain access to this light? Must I remove the entire interior panel(s)? Can I just remove the panel trim just inboard of the light itself? Boy they made this difficult. Thanks for your advice out there.

Harleyguy

Glowing dimly could indicate a poor ground connection. Also the point where the wiring harness passes from the body to the hatch door is a point of flexing wires that often break. Check that area.

georgeb944

Looks like you're in luck, There are two screws hidden under caps that release the light from the rear door frame. Page from the service manual attached...

mrfixit54

When I saw that light glowing dimly I thought of a poor ground too; I had difficulty finding that group grounding point. I then thought that perhaps a wire in the flexible cables at each end of the Avant lid had a break...when flexed I could not see any change...not conclusive. I gather from reading online that these fixtures often fail inside due to a faulty solder connection(s). I tend to lean this way of thinking. Thanks Harleyguy!

mrfixit54

This manual page is like a Christmas present! From watching videos I was under the impression that I must completely take apart the interior trim on that rear door and that I must release the light fixture from inside, nearly impossible! This page proves otherwise...as I mentioned to georgeb944 I have a feeling that this fixture is failing not from a wiring or voltage point but more from an internal soldering connection(s), this as described on online videos. I hope to know more conclusively as I repair this. Once opened up I will check both for power when brake is applied and for voltage. Those little caps may break but if placing a new light that won't matter.

With a OBD code showing this light is out, my TIP trans is exhibiting hard downshifts...I must repair the light in order to proceed. I also have a S.A.P. code showing insufficient airflow detected...I am in the process of chasing this down. I placed a new hose from air filter box to air pump. Had the other hose off, pressure tested with no leaks. I am about to check the kombi valves and so on.

A million thanks to you two guys, I can't thank you enough! I will post my findings ASAP.

georgeb944

Glad to be able to help...

Harleyguy

No charge!!!

mrfixit54

You two guys are the best! You must post daily helping out many members.

With High-Mount Brake Lamp, Avant, Removing and Installing factory manual sheet with image A94-0181 printed I have carefully removed two caps and screws that secure the brake light to the body.

the directions state..."To remove, press brake light tabs -4- and remove lamp toward rear out from opening"

I did pop the interior trim in order to gain access to the two brake light tab slots/tabs. I wish it were as simple as the manual describes but it is not. This is where I hit the brick wall...I have pressed these tabs every way imaginable but can not release this light...grrrrrrr. Most videos on this topic are for platforms other than the C5 (1998-2005).

I am so close to release but I don't want to break this thing. Once removed I can then check for power ect. This seems strait forward enough...but I am probably among the few C5 Avant owners that have tackled this and written about it.

Any further advice is so very much appreciated...please help Mr. Wizard, keep me from this bridge from which I am about to leap!

georgeb944

If a picture is worth a thousand words, a video must be worth ten thousand! Good video by Wolf...

Harleyguy

George gets an atta boy for this video.