Seat belt alarm goes off even when the seat belts are fastened

GECKO1

MEMBER
2010 RENAULT MEGANE
1.5L
2WD
MANUAL
120,000 MILES

Hi, I recently bought the car listed above 1.5 dCi. The only problem I have is the seat belt alarm was going off even when seat belts were fastened. I bought seat belt alarm stoppers off eBay which you connect into the seat belt holder. I put them in. One in drivers seat one in passengers seat. And drove the car and great. No annoying alarm. Then when I had a passenger the alarm goes off again.. So the drivers seat is fixed but the passengers is not. I took the seat belt holder apart and separated two wires which were touching which I assumed was the alarm wires. That didn't work. Looked under the seat saw that a wire had been cut by the previous owner. So I rejoined them. Still didn't work. Took all the sensors out from under the seat. Still didn't work. Disconnected two plastic connections under the seat and it worked. No alarm. But a warning sign comes up on the dash. Airbag not working. The alarm is so annoying I am tempted to drive it with the airbag not working. If anyone has any suggestions how to stop the alarm I would be very grateful. Thanks

3 Replies

STEVE W.

MECHANIC
13,465 POSTS

Welcome to 2CarPros. From your description it sounds like the seat occupancy sensor has failed. It tells the SRS system when someone is setting in the seat and approximately how heavy they are to regulate the firing of the multi stage air bags. When the seat is empty it also tells the SRS that as well. The belt alarm is the result of that fault nothing to do with the belts themselves. Easiest solution would be to replace the sensor as it isn't something that can just be jumpered out as it sends different signals depending on the state it is in.
Replacement involves removing the seat, then accessing the sensor and replacing it. However it is usually a lot easier to just get a replacement used seat and bolting that in and connecting it. That would restore the system.
You could also have a shop scan the SRS system to verify that the sensor is bad. You might want to look under the drivers seat as there is a similar system there and if the PO liked cutting wires you could get a bad surprise if you were to hit anything as the airbags might not deploy at all.