I recently discovered that the seatbelt in my Ram 1500 would not extend after the driver's door light switch broke. It would after the ignition was turned on, and would continue to do so for some time after the ignition was turned off. Fixing the door switch solved the problem. My question is: why is it designed like that? What purpose does it serve to lock the seatbelt if power is lost?

 

Switch closed (broke) usually means door is open, seat belt locks assuming your going to fall out.

 

That would make sense except that's not what heppens. With switch removed (causing the problem) the circuits think the door is closed all the time, and act like the door NEVER opens. The door HAS to sense being open for the seatbelt to extend.

 

I don't know for sure if the switch is normally closed or open but I still think the general theory is correct. Don't release the belt if door open and vehicle moving. There may be other variable involved I don't know about or I may be off in space with the whole theory

I work on Suzuki automobiles and there seatbelt locking is one of two ways, sudden fast movement that triggers locking via mechanical means built into belt retractor or a small explosive squib that activates in case of collision ( triggered by airbag module ).


Buck

 

Thanks, Buck. I took the old switch apart, and it is definitely normally open. You must be right, that there is some other combination of things that factor in. I was hoping to leave the old switch out when it broke so I could listen to the radio when parked with the door open on a warm day and not be driven nuts by the alarm, but I guess that's not to be. I slightly resent the incessant attempts to idiot proof things, but perhaps I underestimate the number of idiots in the world.