I have been scouring the internet for an answer to this, and have come up fruitless. The vehicle in question is a 1983 B250 Van. The front seatbelts have a mechanical connection to a button in the door that is depressed when the doors are closed. I'm trying to find out what purpose this serves. It's not an electrical connection, it's entirely mechanical (housing cable, with a steel inner cable). The seatbelt doesn't seem to behave any differently whether the door is open or closed. The cable runs to a plastic cap on the side of the seatbelt spool opposite the spring side. Anyone have any ideas what this might be designed to do?

Thanks in advance!

 

post some pics

 

Ok, here goes.



Switch on the door which is pressed when the door is closed.



This is the housing on the side of the retractor where the cable from the switch enters.



Looking upwards from undernearth where the cable enters the plastic housing. You can see the inner cable coming out of the housing cable. At the end of the inner cable, there's a steel stop.

 

my guess is some early type of pretensioner but i really dont know

 

So if the door opened, it would lock immediately?

 

That's a release button. When working correctly the seatbelt won't retract until the door is opened.