lawlaw

I've been getting a defective reverse light warning for a while and never got around to look at it...figuring it's probably just a burnt light bulb. After getting the proper tool (8" long T25 torx driver) and replacement bulbs I took out the bumper tail light assembly and put in a new bulb. To my surprise the warning is still there and still no reverse light. Taking a closer look I believe the metal contacts spring on the housing has worked itself loose and it's not making contact with the bulb. The old bulb, was indeed, still good.

Not sure if anyone has the same issue but just a heads up...will need to address this with my dealer at the next service.

joeyalex

Did you have a chance to take your car in for this yet? This error just popped up on my Q5. I pulled the housing out and checked the bulb and sure enough, it is totally fine. I even checked the resistance between the bulb socket and the bulb, and then the connector on the housing and the bulb, no dice, it all looks fine to me. Almost seems like the car isn’t sending power to that one reverse light for some reason.

Parallax

Same thing for me. Got “fixed” at my 10k service and then a month later started doing it again. I’d say 30-40% of the time I go in reverse I get the defective bulb warning. Dealership is 20 miles away and I’ve been too lazy to go back and get it worked on again.

joeyalex

I took another look because this was bugging me and found the problem. I had done a continuity check between the socket and the bulb, and then the pins in the housing that the socket touches, but didn’t do the test with the socket installed.

I found that the socket that holds the bulb wasn’t making proper contact with the housing, therefore no power to the bulb. The little metal pads that are in the housing have little plastic pieces behind them to push back against the socket when it gets turned into the housing. On mine, those little plastic pins had broken off. I could actually hear them rattling around in the housing. This allowed the metal pad to move away from the bulb socket and therefore broke the connection.

So, while better than a weird wiring issue, it means the real fix is a new taillight housing. I bent the pad with a screwdriver to fix it temporarily, but my guess is it will vibrate loose again over time since it has no support to keep it on this position and I’ll have to take it in.

Not the the level of quality I was expecting on this car...it’s really a poor design.

lawlaw

I am dropping off the car tomorrow. My local audi dealer is completely booked for a month out and yes, what you mentioned above is exactly what I find. The plastic bit that holds the metal contact in place broke off and it's rattling inside the light housing. Besides this I have a whole bunch of issues to address...weak AC that doesn't keep up with 90+ heat, side-assist system malfunction so I don't have blind spot warning, the driver side mirror rattles with every bump I hit...

This is my third audi and is definitely one of the worst in quality. Have a 2016 A5 and a 2018 TTs both have been flawless.

BaileyQ5

I had this same issue. PIcked up my '18 Q5 in February and had this come up in May. Took it to the dealer and asked if it was a common issue and all I got was "well we stock these particular units on hand" which I took as a "yes". Dealer had to replace the entire reverse light housing. Like others I am surprised to have this issue after having the car for only a few mos. Makes me strongly consider the extended warranty after I hit 50k..

Gfunk720

I had a similar experience around 2k miles with mine, but am not positive it was the housing. The reverse light on the passenger side stopped working but then started working again. A few hundred miles later it stopped working again.

I brought the car to the dealership where they replaced the bulb. The next time I washed the car the housing filled up with water, likely because they didn't properly seal the housing when reinstalled. I took it back in and they replaced the whole light assembly. Haven't had an issue since.

lawlaw

Got the car back and dealer replaced the driver side reverse light housing. They also found incorrect coding on my side-assist module (don't know how that happened) and did a firmware update.

Nothing was done to the AC and driver side mirror rattle as they claimed "performing to similar Q5/SQ5 on their lot".

raaizin

While researching this issue I found this thread. Same issue with my 2018 Q5. Dealer replaced passenger tail light assembly p/n 80A-945-070-A

s7edgeuser

Seems like I'm having the same issue. A warning popped on the dash saying the bulb is out, took a look and assumed it was out so ordered LEDs. When I went to take the old bulb off, it looked fine but decided to switch to LEDs either way. About 4 days passed and suddenly a warning popped up again on and off for the past few days.

Anyone able to fix this without changing the whole housing?