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Rt rear light out indicator on, lights ok, ground ok

771 views 11 replies 2 participants last post by  Bob_B 
#1 ·
Hi,

First post to this forum, and hope I can get some advice to correct this problem. Here's the story: My 2005 330XI has for the last three years had a problem where the right rear lights out dash warning indicator lights up upon starting the car. Point #1: This only happens in daylight. It never has occurred in the night or when parked in a dark garage during the day. Point #2: It only happens in a temperature range of approx. 45-75F. I have no idea why, it just does. Point #3: I could get the warning indicator light to turn off (and remain off) by simply turning the headlight selector rotary switch all the way to the right, ie., 'on' position. Wait 10 seconds or so, and the rear light warning indicator would go out and stay off. I could then return the switch to the 'auto' position on the far left. In the last two weeks, the time it takes for the dash warning indicator to go off increased to as much as 20 seconds, until yesterday when I could not get it to turn off at all. Point #4: I notice that the warning indicator only turned on after starting the car and after I stepped on the brake pedal. So, I assumed this was a faulty ground on the right rear lighting assembly; the recall one. Although the connector showed no signs of overheating, I soldered a separate ground to that assembly as many have suggested, tested it and am sure it's sound, but this did not solve the problem, and the rear right light out indicator remains on after stepping on the brakes. Point #5: I tested all light bulbs in the right rear housing with a separate 12v source and they are okay. Point #6: I check voltages across all bulb housing and they are within specs (>12v). Point #7: When I was able to turn off the warning indicator by moving the headlight selector switch to the 'on' position, I believe I heard a subtle click, like a solenoid closing, when the dash lights out indicator turned off.

Okay that's the story, and my question is probably obvious: What's wrong with my car? Right now, I'm guessing the lighting module may be defective, but I really don't have any evidence to support this. The garage where I have all the 'heavy' work on my 330xi done thinks it's a ground problem, but if it is, it isn't in the right rear lighting assembly.

If you have a minute and have some thoughts on this, please send a reply. I appreciate any and all help.

Cheers,

Bob
 
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#2 ·
You tested the bulbs and they are OK, but are they really? BMWs test the resistance in the light circuit and will set off the bulb-out indicator when the resistance gets high, often before the bulb actually burns out. After everything you have tried, did you just try a new bulb? The other common problem is when people use bare brass-base bulbs. Need nickel-plated bulb base. Beyond that, I would also suspect the LCM.
 
#3 ·
Thanks for your reply. No, I didn't have the time to buy new bulbs Sunday night, so all I did was check if each bulb lit up when powered by an external 12v battery. (They all did.)

So, I should go out and buy a set of (how many are there, I don't recall) five new bulbs and replace all of them in the rear light assembly? Anyone know what bulbs I'm looking for (item number)?
 
#5 ·
An important point to re-emphasize: This problem does not occur when the car is in the dark. I proved that once again when I checked to see if the plate lights were okay this noon. My car is in an underground garage, and when I started the car this noontime, the right rear lights-out dash indicator _did not_ go off, irrespective of my attempts to make it go off, by applying the brake and/or moving the car in reverse, or anything else. Those actions were the identical conditions that triggered the lights-out indicator this morning in the sunlight. So, this is what leads me to wonder about the light control module or (maybe) the rearview mirror sunlight/rain sensor. Just wild guesses on my part.
 
#6 ·
We also haven't mentioned the "3rd" center light on the rear. BMW doesn't provide a separate indicator for failure of this lamp; instead they have the system throw a lamp-out warning from one of the corner bulbs (I don't know which one on E46), which may in fact be perfectly fine. Just another thing to check.
 
#8 ·
Yup. I vaguely recall that if it fails, it sets off the RR bulb indicator, which is the one that keeps bugging you. It may be unrelated, since you have so many other odd combinations (daylight, etc.), but I thought I would mention it.
 
#9 ·
I hate adding 'red herrings', but this evening I noticed that my headlights are occasionally flickering once in a while. They never did that prior to the latest onset of the dash lights out alert. Again, does this bring any more credence to wondering about the light control module?
 
#10 ·
Just checked out what's involved in replacing the light control module. Not a simple procedure (requires reprogramming), so I hope that new bulbs will solve this problem. Otherwise, I may be forced to use the old black electrical tape trick to cover the dash lights out indicator.
 
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