Hey all,
I've tried a decent bit of Google-ing in hopes of finding a solution, but it's a couple hours later and I'm still in need of some help.

The issue I'm having is that my truck keeps blowing the AC/Horn fuse located under the hood, labeled "20 AMP HORN"

This first came to my attention when the AC in the truck wouldn't kick on. Whenever I attempt to turn on the AC in the truck, it immediately blows the fuse. I have ran a wire directly from the battery to the positive lead on the AC compressor and the AC is able to turn on and operate perfectly.


A few characteristics that I have noted through messing with it all afternoon:

-The fuse does not blow until after I turn the AC on
-The fuse still blows if I leave the AC relay in and take the horn relay out
-The fuse does not blow if I take the AC relay out and leave the horn relay in
-The fuse will blow whether or not the AC compressor is connected to the harness

This leads me to believe that it is not a fault with the Horn, but a problem with the AC wiring somewhere. My question is where to go from here.

I'm hoping someone will have some suggestions before I go digging through all of the AC wiring. I'm assuming that there must be a short in the AC circuit somewhere, but I'm wondering the best way to find it. I do have a multimeter and a Haynes repair manual at my disposal.

I appreciate any help or suggestions that anyone may offer.

 

Trace the power feed wire for the compressor starting AT the compressor, back to the PDC under the hood. (power distribution center) You have a short in that wire. It should be Dark Blue with a Black trace.

 

Didja try swapping the AC relay with a new or at least known good part? It can happen that a reed bends or breaks, and creates a short. It's not common, but I've seen a few fail that way.

With the fault occurring while the AC clutch is disconnected, we can rule out the clutch and the snubber in parallel with it -- that leaves just that dark blue/black wire if the relay is not the culprit.

PS: Grab the '94/'95 Factory Service Manual here. It's more complete than the Haynes manual, has the entire vehicle schematic, and may be more accurate than the Haynes manual. Besides, you want it anyway.

 

I have indeed tried replacing the relay to no effect.

I will begin tracing the wire this weekend and hopefully get to the bottom of things.

Also, many thanks for the link to that service manual, it has a thousand times more information than the Haynes manual and will help me sort through all of the issues related to the truck.

 

That narrows it down, as all that's left is the conductor. You're almost there.

You're welcome. The price is right so there's no reason not to have it, eh?

 

Finally found the source of the problem!

The two wires that run to the plug for the AC Compressor had rubbed through each other's insulation near the rear of the engine inside of the wire loom and it was causing them both to be grounded, thus blowing the fuse.

The AC is working perfectly now, just in time for Summer.

Greatly appreciate all the help in solving this issue!

 

Glad ya got it fixed. Congrats! (and enjoy. )

 

Glad to hear you got it fixed! Thanks for the follow-up.

 

Thanks for posting back that you found and fixed the problem. This will be very helpful for others.