Low freon charge and faulty CCRM (Constant Control Relay Module).
Check under the air filter housing for the PCM (power control module) if you could open it you would see about 5 relays on a circuit board one of the relays is for ac compressor. In general change the PCM.
Maybe the compressor clutch is not being sent power from the switch in the cab. I'd yank the panel out and have a look at the switch. FriPilot
Bad power steering pump
Assuming you are asking about the ac compressor, there would be two possibilities, blown fuse or low on freon.
It would if the battery voltage was lowered enough to cause it not to fire.
what would transmission not to shift in to overdrive
Linkage adjust
check a/c compressor and belt.
If the noise sounds like a power steering whine it could be caused by the A/C compressor clutch bearing or the belt idler pulley.
Your alternator could be bad.
Bad ignition wires
Mabe your compressor is not kicking on for some reason. Check to see if the front of your compressor starts spinning when you turn it on. If it don't check to see if there is power to the wires that go to your compressor. If there is power you have a bad compressor. If there is not check the fuses or relays.