I am new and have a question. I just bought a 1994 f 150 4x2 5.8 L 2 weeks ago. The a/c blows ice cold but stays on all the time even if the a/c is shut off and the fan off. I can even just put the vent on and the air blows out ice cold. The a/c is nice but because it stays on all the time it burns gas when I dont want it on because the compressor is on all the time. Any thoughts? Thanks

 

You're in Florida, the air should never be turned off.
I'd start by checking the dashboard control switch.

 

I checked the hvac head and it seems ok no pulled off hoses or loose wires. The compressor isnt supposed to be on the time is it ?, like it is in the newer trucks. Heat seems to work ok. Need the trim that goes around the control head also having a tough time finding that one! Thanks

 

The compressor isn't supposed to be on all the time. The only thing I can think that would keep it on would be the control switch. I don't know if yours has the separate a/c button or just the lever, but an electrical switch isn't working right.

 

Used to be a cyling switch plugged into the receiver dryer, two wires, unplug it and the compressor should stop. If this is your system perhaps the switch is bad. The large suction line coming from the cabin near the firewall goes to the rec/dryer, unplug the switch.

 

Yeah, or give it a whack and see if it unsticks. Good thought Bill.

 

Thanks I will try that

 

I unplugged the cycling switch and the compressor stayed on! I just cant figure this out my buddy said it may be jumped to stay on all the time. It doesnt make since why the compressor would stay on even if switch was unplugged though. I also dont think that its the controls in the cab because I can turn the blower off and vacuum lines look good. Any other advice?

 

Unplug the electrical connector at the compressor and see if it goes off. Do it with the engine off.

 

I figured out why the a.c was staying on. The previous owner ran a wire down from the wiper motor wiring harness to the compressor wiring harness as a "jump" because as soon as that wire was removed it shut off. Now when the a/c is on using the controls the compressor doenst turn on. Sounds like a quick fix. Any ideas why the compressor isnt coming on? Cycling switch?