Rear Power Window on Blazer

[smittysmith13]

Alright guys...I know this question has been asked before, but I have to ask again. 87' K5, rear power will not work with key anymore. Still works fine from the inside switch. I just purchased the blazer a few weeks ago so I don't know a whole lot about them.

Help...Please!!!

Smitty

 

[K5-Kelly]

Probably has a broken wire where it passes thru the body to the gate. Just check and see if you are getting power at the key switch inside the gate itself. If you don't have power there then start tracing it back until you find where the break is. If there's power at the switch then one of the contacts is probably no good and you'll need a new one. You can tell if you hit the switch by using the key and using an ammeter see if your getting power. Do this with the gate down and open with the latches flipped in the closed position, this way the gate thinks it's closed and you should be able to operate it. Make sure to support the glass so you don't break it. Easy if you have a digital volt meter and just take your time.

 

[smittysmith13]

thanks...will do.

 

[dyeager535]

The switches themselves are a pretty failure prone part (not really common, just one of the things to "fail"), if digging into the tailgate this far, check for voltage as mentioned, if present, tear the switch apart. Assuming the contacts are not pitted/rotted away, clean the contacts up and connect to the wiring, testing if it works before complete assembly.

 

[84ever]

I got my '84 K5 in '87 and the tailgate switch wasn't working. It's not hard to pull the inside cover off with the tailgate down, flip the safety switch by hand, then crank the window out using the dash switch. I always stick a trash can under the glass to hold it up while horizontal, it's just the right height. Then you can get to the switch.

The switch contacts were burned up, nothing left of them. I replaced the switch only to have the contacts burn up again several months later. Fool me once, shame on you, fool me twice..... There's just too much current on that motor for those cheap contacts in the switch.

I installed a pair of power relays inside the tailgate, connected the motor to the relay contacts, and connected another new replacement key switch contact to the relay coils. I think the relay contacts were rated for 30A DC. The dash panel switch still drives the motor directly, although I could have made it drive the relay coils as well.

That was over 20 years ago, haven't had to mess with it since. Oh yeah, I didn't trust the ground going to the tailgate through the hing either, could contribute to voltage drop forcing the motor to draw even more current through the switch contacts. So I added a dedicated ground wire from the frame to the tailgate as well.