Advice required - W129 seatbelt warning light and audible alarm.

[IBN]

Hi Guys

I need some more technical advice. My W129 has developed an annoying habit that I would like to fix - but don't know how!

After I've been driving for about an hour, for no apparent reason the seatbelt warning light on the dash lights up and an audible alarm (which I understand is the seat lock warning) periodically sounds. If I turn off the ignition and wait for about 10 minutes the problem temporarily goes away.

The issue seems to be with the passenger seat - if I raise the seat locking lever, the audible alarm stops but the seatbelt warning light stays on.

I've tried fastening the seatbelt and have squirted WD40 into the seatbelt locking mechanism but the light stays on.

Cheers


Does anyone have an idea of what may be causing the problem and how I can fix it?

[television]

This is not a common problem on the 129060 car


the link fives you all of the pieces and the fault must be a sensor or micro switch

http://www.detali.ru/cat/oem_mb1.asp?TP=1&F=129060&M=103%2E984&GA=722%2E363&GM=717%2E434&CT=F&Cat=515&SID=91

[IBN]

Thanks Malcolm - As usual you are the fount of all knowledge!

[television]

I am sorry that I cant help more, but this is a fault that I have never heard of, but with a simple meter it should be not too hard to find, the dismantling of the seat is the hardest thing

[stats007]

I would think it's the backrest locking microswitch issuing the fault. Either the switch is faulty or you have a problem with the proximity sensor N32/5 (in the 'B' pillar). This convenience feature prevents the seat back coming into contact with the storage compartment.