Willgatlin25

I decided to create a new thread to discuss my rear brake lamp / signal lamp issues, rather than continuing to merge it into my former misfire thread.

To summarize, I am having intermittent issues now with the right turn signal. I was having problems with the brake lamps in the rear hatch but replacing the left harness in the hatch along with a new bulb fixed that problem.

Whats going on now is that sometimes the right signal works fine and other times it starts to flash really fast on the dash, at the same time the signal lamp out warning comes on indicating I have a turn signal lamp out in the rear. So several times now I have walked around to the back with my right signal on and I notice that only the bumper signal is flashing, but the signal lamp in the hatch is not. Other times I’ll walk back there and the hatch lamp is flashing but the bumper signal lamp is not.
Today I noticed that when I open the rear hatch the signals immediately start to flash on the bumper and stop flashing in the hatch. I understand this is normal operation. However when I close the hatch the signals do not resume flashing in the hatch, they still stay flashing only in the bumper. I checked both right and left signals and sometimes they flash in the hatch and sometimes they don’t. If I open the hatch and close it while the vehicle is running the lights don’t resume flashing in the hatch on either side, they only stay in the bumper. Having said that I am only getting the signal lamp bulb out warning showing up on the dash and indicating it’s the rear right signal that’s “out”. But strangely enough I’m not getting any signal flash on the left side in the hatch either, but the dash isn’t reporting a lamp failure on the left side, only on the right.

Sorry that explanation is a bit all over the place and hard to follow but that’s where I’m at.... Confused as hell and all over the place. I have fixed so much stuff in the last few weeks that I finally have my Q7 running like it should. All I have left is this stupid signal lamp out issue and it’s got me stumped.

Built4Sin

Sounds like the car isn't recognizing that the hatch is closed. But I'm assuming the dash doesn't show it open. Have you scanned the car with a Vagcom to see what codes you might have, that haven't triggered the check engine light?

Willgatlin25

Dash does not say the hatch is open. It does show when it’s open and closed on the screen.
Unfortunately I don’t have a VAG-COM. I’ve been doing research on purchasing one of the cables but I need to make sure some form of software is included. I have a cheap little wireless OBD scanner that will give me check engine codes but not even close to sophisticated enough to read those components. By the way check engine light is not on.

I did have my mechanic perform many scans with with Autel computer which gave a full read out of the entire computer system. The check engine light is not on presently but there are two stored codes. One for brake vacuum pump circuit open intermittent and the second one is for a coolant temp sensor. I probably have a crack in one of the junky brake vacuum lines causing a leak but I have no idea what the temp sensor error is about. Engine temp always stays normal, nothing appears to be leaking either.

Maybe with the light issues I should just try and find a replacement latch for the rear hatch and swap it out? I know there’s several little micro switches in there that get dirty and fail. Wondering if that’s where the issue is coming from?

Willgatlin25

I’m going to start with the basics here and just change out ALL of the rear light bulbs first. If that doesn’t fix the issue I’ll look into prioritizing the replacement rear latch mechanism.