When I turn air conditioning or defrost on, it instantly blows the fuse under the dash. I am wondering if this is caused by a seized bearing in the A/C unit itself or if it's something simpler.

Any info would be appreicated

1990 K5 5.7

 

Sounds like a short.

 

try unplugging it from the compressor and see if thatll make the problem go away. and you can even leave it that way if youre not worried about a/c. i have never seen a compressor itself cause a fuse to blow but very possible. try tracing the wires also coming off the a/c compressor. they may be pinched or smashed somewhere

 

What fuse under the dash.. AC? IF so...
{sorry, abig.. I had the screen up, left and came back to it. You're right.}

AC clutch coil.
If you had a seized bearing you'd have a helluva racket and probably a shredded belt.

Pretty sure if you unplug the connector at the compressor that will stop the fuse blowing. Then you'll know you have a shorted clutch coil.

 

thanks guys when it's disconnected from the compressor it doesn't blow the fuse anymore.