I bought my 97 f150 a few months ago and I have been having problems with my air. When I saw the truck of the lot the air worked pretty good but when I got it home I check again and it was blowing hot so I took it back and the same thing happend.
The first thing I checked was the freon. I discovered that it had a small leak in the valve. I relpace it and refiled it. I found out that at idle it would be ok but when driving the fuse to the compresser would blow. Im not sure but i think the compresser is supose to cycle on and off but mine doesnt. The compresser and the revers lights are on the same fuse but I tested the ligthts with the air on and it not that (as far as I know) My question is has anyone had this problem before or can anyone give some advice. Your help is much appreciated.

 

Well, I kind of had a similar problem in my old Chevy. Basically, I had a leak also which I got fixed and re-filled the freon. BUT, the air still didn't work...fuses were fine. I found out the it was an air-flow sensor that hooked up to the compressor that was bad. I replaced it and everything was fine.

 

Welcome to FTE! Hope we can help.
I believe the only electrical connections going to the compressor are for the AC clutch. Try unplugging at the compressor and replace the fuse, then drive it for a while. If the fuse blows I'd look for a short to ground.
The compressor should cycle on and off - more frequently in colder weather.
If the freon is low, the compressor (actually the clutch) will never cycle on.
Let us know what you find out.
Again, welcome to FTE.

BTW - I'm going to move this to the A/C forum where I hope you'll get more input.

 

I did what you said BrianA and It blew again. Do you know how to correct this problem or where to start looking? Also i found out that my heater does not blow hot air but the blower works fine. Do you think the thermostate is a fault? I checked the heater core lines and its connected but I dont have alot of time to mess with it can you give any pointers?

 

Several things to look at.

The blend door in the dash may have broken and is not letting heat in. Check your heater hoses to see if hot coolant is moving through the heater core.

Your AC compressor should not be blowing fuses. I agree with BrainA that you have a short. Something else may be causing to overload the compressor such as incorrect pressure/freon in the system?

 

Your A/C sounds like a job for a pro. You can change parts and "top off" the freon level; but, without the proper tools, specs and know-how, you are risking damage the compressor, o-rings, condensor, and accumulator. Take it to a person that might save you hundreds of dollars, that is, a certified tech. You may have a simple problem such as one leaky o-ring, but if you do not repair the system and charge it with the correct amount of oil and refrigerant, you risk destroying the compressor and after that dies you may need a new accumulator, and possibly a new condensor.

I wonder if the wire you disconnected at the a/c compressor was totally out of the circuit? The wire for the clutch-plate coil goes up to the accumulator pressure switch. You may try disconnecting that wire also, to isolate your overload problem. There might be a connector sticking out of the accumulator, this measures the pressure in the evaporator and cues the compressor on and off. Don't quote me, I never owned a '97,... 92 is as far as I go.

If you don't get hot blown air. #1 check your coolant and thermostat this weekend. I drove around for three years once, and froze in the winter, all because my thermostat wasn't closing up.If your temp gauge is staying at or just above the"C" mark then you have a bad thermostat.. #2 your ventilation doors aren't working right. Maybe the door that opens to let fan air pass thru the heater core is stuck down. As you move the heater temp controls from hot to cold you should be able to hear the door shifting positions. One for air over the evaporator(A/C), one position for air diverted to the heater core(heat).#3 Maybe a mouse built a nest in the duct. It only takes a week for a rodent to move into a parked vehicle and set up housekeeping. Good luck..

 

I finally was forced to go up under my truck because of some type of counter weighted ring on the drive shaft yoke. I went ahead and took a look at my trany saw a couple of conection and disconected one. I turned out to be the switch for the reverse light . So my a/c and the blend/mode door has a temp fix.

Thanks for all the help.