Heater/window problem

[Fancy]

So yesterday night I hop in my 90 blazer and I can't roll up my windows and the heater dosen't work! I checked most of the fuses and nothing then suddenly the heater kicked on and the window worked but the heater imidiatly began to cycle on and off then after a minute or two of that it worked just fine????? I don't know where to begin except double check all fuses?

 

[British Slave]

Doubt it's a fuse, a blown fuse is a blown fuse. You have a bad ground or a bad connection somewhere.

 

[Fancy]

That's kind f what I was thinking! Haven't had much time to check into it yet but I did find that my speedo dosen't work as well but it is very hit and miss sometimes it all works fine and other times nothing! Any body have any ideas on what I should check first?

 

[89GMCK5]

As mentioned grounds. Most intermittant electrical issues can be traced back to bad grounds on these trucks. Go over all of your grounds, and replace them. I found one recently on a buddies jeep that look to be in good shape, but replaced it because it was part of a suspect circuit. Turns out once I skinned the insulation back, the wire was about disintegrated inside.

I plan on replacing all of mine, starting in the engine compartment, and going all through them. Battery to radiator support, block to frame, etc. I know there are a lot of circuits in the cab / dash that share a ground up there behind the dash.

It's time consuming and can be a bit of a pita, but plan on doing it. Either here and there, or make a day of it, and be done with it.

 

[Fancy]

I agree it sounds like a ground but i already replace most of them with larger wire and better connections but like stated i need to go through and check and replace them all as i might as well any way! I was just thinking someone might know which to start with that might save time but i have a lot of wiring to fix anyway so might as well make a day of it.

thanks for the replies guys!

 

[1AAuto.com]

I'd also check around for a frayed wire.