I have searched the forum and tried to find a person with a similar problem to mine but no luck. I have a '91 SR5 pickup with the 3.0 and 4x4. The A/C has performed way beyond my expectations until last week. I was driving on a fairly hot day and all of a sudden my cold air got hot. I looked at the A/C button and the green light was off. I did some research and found the fuse behind the glove box, it was blown so I replaced it and the A/C worked for about 15 minutes and blew the fuse again. I don't know if low coolant could cause this problem, bad wiring, or if the clutch could be going out. But for it to work for a while before blowing the fuse makes me think that this is not a short in the wiring. I don't have any schematics on the A/C system itself or of the electrical diagrams for the A/C system either. I saw someone on the forum had a copy the FSM, any help would be greatly appreciated.

 

Are you sure the fuse amperage rating is the same as the one you pulled?

 

It had a 10 amp so I replaced it with a 10 amp the first time it blew and then with a 15 amp and blew it too.

 

Try a 50 amp...Just kidding! Low refrigerant would not cause this, over heating can cause the a/c to turn off but should not blow a fuse, sounds like and electrical problem to me. You might have a bad wire or a bad switch somewhere.

 

i have an electrical fan in mine and it is wired in with the ac fan on the front as well...When i did my timing belt i crossed 2 wires on the electric fan and blew that fuse that is when i realized whaat i had done. Do you have an electric fan?

hope this helps

 

My votes on the clutch.

 

maybe try disconnecting the wire at the compressor, then turn your a/c on with the fan and see if it blows the fuse. this would check to see if your short was at the compressor clutch. basically, you have a short somewhere, its just a matter of backing up down the circuit to find where the problem is.

 

Im having the same problems.

subscribing

 

I replaced the fuse and the AC worked fine for about fifteen minutes and then the fuse blows, the AC light goes out and the air loses it's cold shortly after. The blower for the AC never quits blowing just the function of the compressor. I'm no electrical expert, but if there was a short in the wiring on the compressor, would it not blow the fuse the instant I pushed the AC button instead of waiting fifteen minutes or so?

 

Put ya a targo switch on the clutch...... go around the fuse all together.. Its a drastic redneck fix but it would keep ya cool

 

It might not be shorting out all the time...vibration or heating may flex the wires enough to make them touch. Also if you have a wire that may not be totally intact, in other words not enough to handle the current needed, it may heat up over time and melt the fuse (too much resistance).

 

whats a targo switch?

 

toggle switch, Ive heard it called both

 

learn someting new everyday. i wouldnt put the compressor on a targo switch, this would cause it to run all the time, which could be dangerous to the compressor should the system get low on freon, plus there is a thermistor(i think thats what its called) in the dash that shuts the compressor down at about 38 degrees or so. this may also cause your condensor to freeze up, since your targo switch has defeated that. so, you could put it on a targo switch, but it seems to me time putting the targo switch in could be time better spent tracing down the real root of your problem.

 

I guess you didn't read the "extreme redneck fix" part of my post.. but i get the feeling you just look for things to complain about anyway.. so it didn't matter..Ive always done things different from other people but i get the same result.. in the end thats all that matters to ME...

 

As the clutch coils and bearings heat up they expand toward each other and then short out.It may take 15 min. for this to happen.

 

take it easy pardner.....i am mearly trying to advise the person who posted this topic that the targo switch is not the best way to go. i personally have had to fix the end result of someone doing this. actually they just jumped the low pressure switch. the freon leaked out, but the compressor kept running. this in turn destroyed the clutch, coil, and compressor. contaminated the entire a/c system, violently threw the belt off taking the rest of the belts off with it leaving the truck stranded 50 miles from home.

 

I finally got back into town last night and had a chance this morning to look at the compressor with the skid plate out of the way. There is quite a bit of oil on the underside of the compressor. I'm afraid that I have developed a leak in the compressor housing somewhere or it may be power steering fluid that has dripped down from the p.s. pump while I changed out my p.s. gear box. If it's oil that has leaked out of the compressor, would it not have leaked most of the freon out as well? Where do you connect your refer guages on this AC system?

 

when your a/c is working, is it cold? if so i wouldnt worry about the leak for right now. i would be chasing down your electrical problem first. i really dont think the leak and the electrical problem are related. if your system becomes low on freon it shuts the compressor off to avoid catastrophic failure. you are correct though, if your system is leaking oil, it is probably leaking freon.

 

Clinista--i would take 3yotys and Nie....-25 advice. YOU HAVE TO FOLLOW THE SHORT. That is the way it works--plain and simple.

Here is a simple reason why it may take 15 min to blow--Kinda like a water hose--when you open it all the way there is very little pressure. However if you open it a little--well then over time it will build pressure and when you finally open it all the way that pressure escapes. eletricity is the water and pressure is building. The wire is the hose--resistance/pressure build and instead of blowing/melting the hose/wire--the fuse blows. Unplug the Compressor and see if the circuit still completes--if not then it is probably time for a new compressor. Good luck and good time to switch to R134a