BMW problem: any experts?

Just had a very strange experience and wondered if any of the car experts on here can help.

The car is a BMW 3-series E90.

For about a week I’ve had the amber ‘bulb warning indicator’ showing up on start up. Sytner read the key and diagnosed a front parking bulb out. I have seen myself that the bulb needed replacing.

I just took the car to a local garage for the bulb replacement and the light (which I had seen not working) now works and the warning light didn’t come on.

I must have looked like a right idiot.

Any explanation?

I would be inclined to believe a faulty sensor, but I have seen for myself that a light which wasn’t working now is working. Could the bulb be loose or have a poor connection?

The only other strange thing is that over the Christmas period the service warning light came on every time I started up. No service or MOT is due so I put that down to the car not being used much during the holiday.

I wondered if the sensor might be faulty but as I said Sytner read the key and diagnosed only a parking bulb replacement.

A weak battery can cause intermittent sensor faults.

I had the same problem on my wifes mini cooper s. Key diagnosis just said needed a bulb replacement, turned out to be a faulty connection in the bulb socket (not sure correct term). Once that was replaced we had no more problems.

Quote:

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Originally Posted by CaptainSlow

A weak battery can cause intermittent sensor faults.

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Very true. Our 7 series lit up like a Xmas tree on occasion when the battery got weak.

Definitely try the connection at the bulb. It could even be that the filament has touched back together again after breaking in the bulb itself, this will go again fairly soon though I suspect

Quote:

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Originally Posted by CaptainSlow

A weak battery can cause intermittent sensor faults.

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I've had all sorts of strange electrical glitches on a BMW too when the battery was on the way out too albeit this sounds more like a connection issue with the bulb rather than a sensor.

The giveaway on most BMW's that the battery is an issue is that it turns the radio off the moment the engine is switched off rather than when the key is removed or doors locked. Next phase is it puts everything in standby mode so you find the clock has reset in the morning. If OP has experienced either then check the battery.

I had a similar issue not long ago, which turned out to be a dud bulb holder.

Easily diagnosed with a multimeter and fixed by replacing the holder.

Check the contacts on the bulbs.

I've had this issue before where the car shows up intermittent failures, caused by corrosion on the contacts.

I had a similar issue with my E90 a few years ago, I think initially it was a bulb fault but it then caused a failure in the footwell module (FRM) that was quite costly to replace. I would suggest getting is sorted ASAP.


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Can issue

Checking the contacts for corrosion or heat damage would be what I would do first.

As others have said,a tired battery will throw up nuisance faults on the OBC,I know from owning a couple of e92’ in the past there was a recall done on the rear lamp holders.The self check on startup for lamp outages is very sensitive to corrosion on all points of cantact.Change the bulb and use emery paper to clean the lamp holder contacts.


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To me the fact that you saw the bulb not working would point to the bulb socket/contact rather than a tired battery.

If that's a very strange experience you lead a very straightforward life.