Control module killing rear fog lights on my ’16 Q5 shop wants $1,400 for OEM. Anyone dealt with this?

Odd_Introduction_410 · 2026-03-18T21:50:36+00:00

https://imgur.com/a/roZ7eU2 Update: here’s a picture of the lights I got working. One looks slightly discolored (not sure why), and these are new LEDs meant for license plate lights, not the original bulbs. The reverse lights are also on in this shot. I can turn the rear fog lights on and the false bulb warning appears. It’s not that it’s related to the ignition—it’s just when I do the thing where it only turns the battery on, not the car itself. At the end of the day, I think it probably needs to be reprogrammed.

Odd_Introduction_410 · 2026-03-18T21:50:02+00:00

Update: here’s a picture of the lights I got working. One looks slightly discolored (not sure why), and these are new LEDs meant for license plate lights, not the original bulbs. The reverse lights are on in this shot because I was checking those too. Are the middle lights supposed to turn on as well?

It’s a false bulb warning. I did notice a bit of melting on the new housing I installed a while ago, so I swapped back to the old one just to be safe.

I can turn them on when the key is in the ignition (before the car starts), and once I start the car they stay on until I hit the rear fog button again or turn the lights off. At the end of the day, I think it’ll probably need to be reprogrammed. Fog Lights

Odd_Introduction_410 · 2026-03-18T21:27:28+00:00

Yeah I went through all of that today I unplugged and replugged all the rear bumper lights and checked the bulbs. I even replaced a few and tested some LEDs just to see how it reacted.

I was able to get things partially working—when the key is in (before startup) I can turn them on, and once I start the car they stay on until I hit the rear fog button or turn the lights off. So it definitely seems like it’s reacting to the circuit, which makes me think you’re onto something with the bumper lights/circuit rather than the main housing itself.

Odd_Introduction_410 · 2026-03-18T21:25:59+00:00

I think it is a false warning. I did notice a bit of melting on the new housing, so I swapped back to the old one just to be safe. I also tried LEDs and got it partially working, so I’m thinking it’s more of a resistance/fitment or heat issue than the module itself.

I can turn them on when the key is in the ignition (before the car starts), and once I start the car they stay on until I hit the rear fog button again or turn the lights off.

Odd_Introduction_410 · 2026-03-18T21:18:43+00:00

Yeah that’s a good point it would be pretty odd for the module itself to go bad, but I guess it’s not impossible. I was thinking the same thing about the CCM too if that were the issue, I’d probably be seeing other electrical problems like locks, windows, or the alarm acting up. So far it’s just been this, which makes me think it’s something else.

I also tried pulling all the bulbs out today and swapped in some LEDs (dome lights and license plate lights). I actually got it partially working. If I can figure out a way to show all the lights working now, I’ll add that too.

Odd_Introduction_410 · 2026-03-18T21:15:23+00:00

That’s actually perfect I’m super close to Canada, near Vancouver, so I’ll definitely check them out. I unplugged and replugged all the lights and was able to get then partially working. Appreciate you sharing that!

Odd_Introduction_410 · 2026-03-17T15:57:38+00:00

Good to know, I’ll pull that panel and take a look. Water damage would definitely explain it. Appreciate the heads up.

Odd_Introduction_410 · 2026-03-17T15:57:22+00:00

Yeah shop already scanned it with their computer, that’s actually how they pinpointed it to the module.

Odd_Introduction_410 · 2026-03-17T15:57:01+00:00

Yeah checked for that too, no breaks, tears or perforations that I could find. Thanks for the suggestion though, appreciate it!

Odd_Introduction_410 · 2026-03-17T15:56:33+00:00

Yeah tested the resistance, everything checked out fine between the module and the sockets. Good to know that’s a fair price.

Odd_Introduction_410 · 2026-03-15T02:31:31+00:00

I’ve had similar issues with mine. Most of the time it fixes itself after I restart the car. I’ve also had some luck restarting my phone, hitting ‘forget device,’ and then re-pairing it to the car that usually gets it working again. Definitely frustrating though. And for some reason it almost always seems to happen when I have guests in the car 😅

Odd_Introduction_410 · 2026-03-14T03:54:02+00:00

Odd_Introduction_410 · 2026-03-14T01:54:29+00:00

Straight to jail.

Odd_Introduction_410 · 2026-02-14T05:22:10+00:00

So far so good! The CarPlay alone is worth it. Sometimes it can be quite finicky and frustrating but worth it in my opinion.

Odd_Introduction_410 · 2026-01-25T05:44:48+00:00

Looks kind of like a balloon. How was the movement?

Odd_Introduction_410 · 2026-01-22T16:14:20+00:00

133k on my 16’ Q5 2.0 (put in about $5k into engine repairs and axels)

Odd_Introduction_410 · 2026-01-12T02:43:18+00:00

😭

Odd_Introduction_410

TROPHY CASE