False bulb failure warning.

!997 528i. Graphic display shows occasional o/s rear or brake bulb failures. Warning could come on, then a mile down the road go off again. A few minutes
later it might come back on. Only just started BTW. For the last year it's been fine with the same bulbs.
All rear bulbs have been checked when warning was showing, and all are working. Have removed and refitted bulbs, and tried swapping similar bulbs. Nothing seems to make any difference. I'm now thinking sensor module, relay, whatever.
I'm probably misnaming it or something, but googling doesn't come up with any info that might solve the problem. Any suggestions welcome. TIA Mike.
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Could be the relay box that detects failures. Could be the connectors getting a little corroded. Could be that stupid twist-base socket arrangement. Clean EVERYTHING carefully, coat EVERYTHING with dielectric grease, resolder all the cold solder joints in the sensor box in the trunk and then pray. It takes very, very little series resistance in the circuit to trigger the alarm. --scott
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"C'est un Nagra. C'est suisse, et tres, tres precis."

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What other arrangement exists for cars? ES types are likely to work loose through vibration.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Oh, on the car described, there is a plastic base that the bulb twists into. Then THAT base is inserted and twisted into a flat plate with contacts on it. This means the number of possible contact failure points is doubled. --scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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On an E39? Mine doesn't seem to have that arrangement - unless I've missed it.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Oh, I'm sorry. I thought the original poster had an E34. --scott
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I have had this on my 525 touring since i got it...quite common fault sometimes doesnt do it for ages, then suddenly...then goes again for ages,

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Common - usually burnt or dirty contacts on the lamp unit NOT the bulb. Pill the lamp unit and check for erosion on the contact strips.
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Sir Hugh of Bognor

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