[RayLivingston]

My '07 335i has a persistent, but bogus, fault - it complains about the left-front side-marker light bulb not working. But it IS working just fine. What's more, I swapped first just the bulb, and then the whole light assembly, between the left and right sides, and the fault is always reported on the left side.

I can't see anything this could be other than a fault in the wiring, or a bad input on the controller.

Any other ideas?

Anyone know where that controller is located, and where the wiring is routed?

We live out in the sticks and do sometimes get rats making their homes in our cars, so its not impossible a wire got chewed through. Its happened three times to the E46 over the years - all very easy to repair, thankfully.

Regards,
Ray L.

[tlow98]

You chose the ground for the light?

[nissubaru]

Originally Posted by tlow98

You chose the ground for the light?

What do you mean?

I have a similar problem but for one of my tail lights. All the lights seem fine though. I believe I have to hook up INPA to clear the code. You may need to do the same through INPA

Another member I PM'd about the issue mentioned that the system is smart enough to use another bulb in place of the dead bulb as a brake light which I thought was interesting to know. I doubt that's the case for you though since there aren't any other bulbs to use in place.

[John 070]

Interesting, when I got that in the rear tails, with bulb being good, the fault followed the bulb, and when the bulb was replaced, no more fault. What is in common with your issue, is that the bulb was fine, but there was a fault.

[RayLivingston]

Originally Posted by nissubaru

What do you mean?

I have a similar problem but for one of my tail lights. All the lights seem fine though. I believe I have to hook up INPA to clear the code. You may need to do the same through INPA

Another member I PM'd about the issue mentioned that the system is smart enough to use another bulb in place of the dead bulb as a brake light which I thought was interesting to know. I doubt that's the case for you though since there aren't any other bulbs to use in place.

Clearing the fault does nothing. It comes back shortly.

On the E46, the ground wiring to the tail lights was dodgy, and could cause many bad-bulb warnings. The fix was to disconnect the ground wire from the metal ground plate on the light housing, and re-attach it with a more secure, and better, electrical connection. Perhaps the E90 tail lights have the same problem?

Using the wrong bulb, or a bulb/socket with corroded connections will cause faults, even though the bulb does light. So, changing the bulb makes sense. But in my case, it's perfectly happy with either housing and/or bulb on the RH side, and unhappy with either on the LH side. So I think the problem HAS to be in the wiring, not the bulb or socket.

Regards,
Ray L.

[Indyeah]

Another '07 here with the same issue. Randomly I get the bulb warning light and I'll go again all the way around and check all the bulbs and they light up.