Whats this switch
 

Can anyone tell me what this piece is thats circled in the photo? I have a hole on each side of my K5, not sure what goes there. I would have guessed its the dome light switch, but my 78 has them installed on the front door jamb

Re: Whats this switch
 

Seat belt release. They were like that through like '87 I think.

Re: Whats this switch
 

How do they function? Ive got shoulder belts on my truck, but its currently disassembled. I remember them working fine without the releases?

Re: Whats this switch
 

It may indicate your shoulder belts may not be performing properly. Otherwise, I think they lock up....but I'm not positive. Or won't suck in tension..don't remember.

My 89' has them, so I'd say they ran all they way to 91'.

Re: Whats this switch
 

This..but they ran all way thru '90. Some '91 didn't have them as GM switched seat belt suppliers. I have a nos set without the button.

They work when you open the door, the belt retracts. Button pushes a tab and spring tension releases, winding up the belt. Pretty simple. The lock is different from the release. A hanging weight, looks like a fishing weight, works on gravity to lock up.
9 times out of 10 its just dirt inside that stops them from working. Sometimes the clock spring is broken. I have pix of them all blown apart if you need.
I have many a day into fixing Blazer/Jimmy belts.

A little fun fact...the passenger belt can be swapped with drivers side. Just flop the reels from the retractors behind the plastic cover. Figured that out trying fix a frayed driver side.
These are a life saving parts so don't fool with them unless you are 120% confident in your skills.

Re: Whats this switch
 

I meant my truck is disassembled, not the belts. The belts worked fine before I took it apart and it had no release. Will the factory belts work without the release or does this mean someone has changed out my belts?

Re: Whats this switch
 

You say they worked before you took the truck apart, then they will work after, right?
Belts retracted when you unclipped it from the female end?
Maybe somebody put earlier '76-'77 belts in it.
Pull the belt all the way out to where you see the tag. Tell me the part number on that tag and I'll tell you what yr those belts are.
78-90/91 belts all had plunger and yes it needs to be there to work properly.

Re: Whats this switch
 

Thanks for the help. I havent put the truck back together yet. Its been apart for a while. I just noticed that I had a hole in door jam and nothing to go back in the hole, so I started searching for parts. I will test it all out once I get it back together. Hopefully soon, but prob not!

Re: Whats this switch
 

Hope it helped! Owned/parted out over 40 Blazers over the yrs.
I had to think about for a second but they couldn't be 76-77 belts.
They used a different set up for belts because of the floor pan in the rear.
'78 was first yr for the new footwell rear floor & flip/fold rear seat. The belts moved completely to the b pillar where 76-77 had a mount on the floor behind the front seat.

Re: Whats this switch
 

Does anyone sell these new?

Re: Whats this switch
 

I've seen those out of alignment and it will rub on side, make sure the pin is centered, over spray can make it rub, I'd clean them and you might find debris inside