I have a f150 07 5.4l. My a/c is going on and off. Compressor is new and tested functional. I suspect the wires going to the sensor on the dryer, but shorting the pins does not change anything, maybe further down. Wires tested at the relay. When the a/c is switched on, one wire does not always get voltage a the relay.
Control is 3 ***** manual with a/c buton. Anyone have any idea?

Thx

 

Going off as in hot to cold? Or no blower then blower?

 

No the power to the relay, so to Compressor

 

On the drivers side on the fenderwell under the hood is the compressor relay i think. Have you pulled the relay and try to jump power to see if you can get it to turn on? Also i think these relays have an overheat feature that if it gets too hot it wont function till it cool down. I had one controlling the power to the rear of an ambulance that was getting too hot and wouldnt function for a min or two until it cooled down.

 

may be your actual ***** and a/c button. Im not sure how to test it but I had this problem in a older f150 about 10 years ago. I just found a new cluster of ***** and button at a salvage yard. I think I paid $30 for it and it fixed the issue

 

Ok, Compressor tested ok, relay tested ok, cycling switch seems ok. Look like the relay does not get the input signal from controller.

 

time to chase some wires! good luck brotha!