Seatbelt light always on - suggestions?
 

Hey everyone :cool:

Wondering if anyone has any ideas what's causing this. I've got an 04/95 XJ sport (OBD1 obviously), and my seatbelt light has been on permanently for months now. My XJ doesn't have the seatbelt sensors to turn it off when you clip in your buckle, from memory the seat belt light comes on with ignition, and turns off roughly 5 seconds later automatically. An OBD1 thing I guess. The only seatbelt related wiring I have is the red/green and black 2 pin wire down by the passenger seat that, if I jump the two pins, just makes the buzzer sound. But again, neither front seats have any kind of wiring for any buzzers or warning lights anyway.

What else could cause the seatbelt light to come on and stay on? Being a pre update and obd1 I'm sure it's a very simple system with scant few possibilities, but it's just an annoyance I'd like to resolve. I did nothing before it came on, parked it one night after work, and the next morning the light was on. And no, I'm not just taking out the bulb :hammer:

Cheers :lol:

Try maybe reset the pcm by disconnecting the battery cables from the battery and once disconnected touch them together for a few minutes than reconnect the leads to the battery and see what's happening .
Had once an issue with my van showing knock sensor fault but there was no such thing on the engine .
Researched a bit on the net with not much luck but one of the assuption was that the mapping data file in the pcm somehow got corupted by possible strong magnetic field and changing a value of 1 bit to 0 bit (or the otherway).
Had to hook it up to the obd reader and do the reset to factory setting (map file) and fault was gone .
This could be not your case but this is something very rare that can happen .
Before you disconnect the battery leads check the radio if it has a password lock .

I had that seatbelt lamp taken out 20 years ago to replace another lamp in that cluster (XJ 95 Sport) that was no longer working - maybe the check engine lamp.

Could there be a recently changed lamp somewhere outside that may be incorrect? I recall a mechanic fitted an incorrect lamp outside (brake) that sent my inside lights switching on and off every time I pressed the brakes. The bulb needed to have two contact points instead of one.

Thanks for the input guys :)

I've 'fixed' it for now... It was the chime module under the dash, just beside the fuse panel. I really don't know why this would trigger a seat belt light, as it has wiring for the seat belt buzzer which I confirmed works any time I short that two pin seat belt connector, but I dug through wiring diagrams for an hour straight and NONE of them show the chime module having ANY interactions with the seat belt warning lamp at all! It's a head scratcher, for sure. It's also incredibly hard to get accurate wiring diagrams for these cars... I have a few different diagram books for 1995 RHD XJ's and they're all different, and none of them show a 6 pin black chime module like mine has, only the 8 pin version (Pink / Blue), so they're not that great like that.

I opened up my chime module, and honestly it's visually perfect - all windings intact, no damaged wires, no broken solder, nothing. My only guess is there must be an internal failure / break on one of the tiny windings somewhere, beneath the outer layers where it's not visible to the naked eye. I know this thing is one of the most common parts to just throw away for 99% of XJ owners, but I prefer to learn how things work, at the very least, before I do away with them. This one has me stumped as to how it's triggering the seat belt warning lamp, as no wiring diagram shows it having any interaction with anything beyond some basic ground connections, and the seat belt buzzer wiring... I'll work it out eventually, some day. Some pics of the module for those who are curious :)

https://www.ausjeepoffroad.com/forum...b97a1d9c34.jpg

https://www.ausjeepoffroad.com/forum...b97ad882bb.jpg

https://www.ausjeepoffroad.com/forum...b97c0337b1.jpg

Got the feeling that the seat belt light is controlled by the PCM .
Just wandering if you short the 2 pins and the light and buzzer comes on
would they go off after few seconds or after you turned ignition on ??

Have you tried plugging the seatbelts in with no one on the seats to see if that fixes it. I suspect there are weight sensors in the passenger's seat, that maybe stuck.

Seat belt light is operated by that unit and even though an eight pin module is shown in the fsm it looks like only six pins are used anyway. The seat belt input is from the buckle.

If the module is plugged in and the connector to the drivers seat belt buckle is unplugged, when the ignition is turned on if the light goes out after 4-8 seconds but comes back on when the seat belt buckle is reconnected, then the switch inside the buckle is stuck on.

If the light doesn't go out the timer or contacts in the unit are stuck on.