Fasten seat belt light - behavior question

[jsnppp]

Hi,

I have a 1991 318is. Trying to troubleshoot my fasten seat belt warning light located up at the roof in the center near the sunroof crank.

Current behavior is the light comes on for about 5 seconds once the key is turned to position 2. No buzzer.

The light goes off and won't come back on. Doesn't matter if the belt is fastened or not.

Feels like it should turn on whenever the seatbelt isn't latched. Possible a buzzer too.

Can someone confirm their (stock) seat belt behavior? I know most people disconnect the bulb/buzzer. I just want mine to work before I decide next steps.

Thanks!

[uturn]

My light does exactly as you described.

"Current behavior is the light comes on for about 5 seconds once the key is turned to position 2. No buzzer.

The light goes off and won't come back on. Doesn't matter if the belt is fastened or not."

And I love it for doing just that!

[jsnppp]

My light does exactly as you described.

"Current behavior is the light comes on for about 5 seconds once the key is turned to position 2. No buzzer.

The light goes off and won't come back on. Doesn't matter if the belt is fastened or not."

And I love it for doing just that!

Ha ha - I get it! I don't want the buzzer necessarily but I would like the light to work right.

I don't think it's the right behavior because why have the seat belt switch at all?

Maybe it was something people did back in the day and it's a known "fix".

Thanks for the reply!

[jsnppp]

Ok, when in doubt go to the manual:



The behavior is that the door chime and seatbelt fasten light should both be activated when the key is in position 2 and the seatbelt is not fastened.

I either have a bad relay or a wiring short...

Famous last words :-)

[slippery]

Let us know when you figure out the problem as mine works the same way yours does currently.

[Pro1914]

Works the same exact way as mentioned on both of my E30's.

[jsnppp]

Interesting, feels like its working as designed, yet there is still a clear path to a chime + light if seatbelt is unfastened while car is running in the diagram.

I checked my wiring and it appears to be correct. The question mark is the relay, which I'll check tonight.

Thanks folks,

Jason

[jsnppp]

So, upon further review of this system and diagram leads me to conclude it's working as designed. I bench tested the relay and cannot see how the act of fastening the belt will trigger the light/alarm.

Here is the final observed behavior.

When door is closed, driver is in seat, seat belt IS NOT fastened and turns key to position 2:

• Door chime will ring for 5 seconds
• Seat belt light will flash for 5 seconds
• Both light and chime will then stop

When door is closed, driver is in seat, seat belt IS fastened and turns key to position 2:

• No door chime
• No seat belt light

When door is OPEN, and key is turned to position 2 the same thing happens as above except that the door will continue to chime until the door is closed. Seat belt light will turn off after 5 seconds.

To my mind this is odd behavior. I'd think that if the seat belt is unfastened at any time when the key is in position 2, the chime should ring and the light should flash. Annoying, yes.

I'm guessing they were still figuring out how things should work back in 1991 :-)

Thanks for listening and providing data!

~Jason