A/C not cycling

[2man]

My a/c compressor is wired direct. This is something that was done by some genius at a shop. I cant figure out where it should be wired to keep it from freezing up. Runs great at an hour or less anything more and it freezes up.

[64Trvlr]

One thing you can do without rewiring is to set it for recirculate and turn the temp up a bit (warmer). Part of the problem you have is the humidity in the air is freezing on the evaporator and restricting the air flow into the cab. But by going to the recirculation mode you recycle the already cool air inside that has doesn't have as much moisture in it so it won't freeze up as fast if at all. If I had a wiring diagram I would be more help.
:cool:

[porchpiggy]

I was just messin with this the other day on my 88GW. Don't know how similar it is but, my pressure sensor is on the line at the passenger side fender (it was under a hose, hidden). the wire from the comp goes to the sensor, back out to an orange wire that goe to the control module located up under the dash, above the gas pedal. I don't know which part controls the cycle function.

My compressor was not coming on, and I suspect the control module under the dash is the problem, but when I ran my compressor wire hot, it blew way cold air. So for a temporary fix (eventually I do want to have it as it should be) I ran a fused switch to the dash, back out to the wire going into the pressure sensor, and I manually turn on the compressor when I run the A/C. I don't drive the truck very far, very often, but for now I can run A/C, and reach down and switch the compressor off every once in a while. It's my understanding that this is not particularly dangerous or anything, but that it is important to not by-pass the pressure sensor. :cool:

[Lindel]

It sounds like your freon charge is a little low to start with. It shouldn't freeze, especially with the heat we've been having.

Like Trvlr says, turn the temp setting up a bit, and it'll cycle on and off. BTW, you don't have a recirculate option, just a min temp setting.

[64Trvlr]

Lindel
Thanks for letting me know about no recirc option. The heat has nothing to do with freezing, it's the humidity that is the problem. When you cool the humid air the moisture condenses and freezes on the coils and blocks air flow.
:cool:

[Rex]

Sounds like your Thermistor might be bad.
It's in the unit on the right side near the blower. You can jump the connection to see if the compressor kicks on. If it doesn't, the A/C controller under the drivers side is probably kaput. The Haynes manual had a pretty good wiring diagram of this and I found out that first, my blower resistor was bad, then the a/C controller, then the thermistor. I haven't replaced the thermistor yet, but have it jumped. This will allow icing if you aren't carefull. I have one on order.
By bypassing everything and just jumping the clutch, you won't get the thermistor to work and have icing.