So my 2005 Suburbans ac has got me yanking my hair out. The ac works on and off almost like the compressor isn't kicking on. The rear ac is the same, sometimes it kicks on a blows ice cold...sometimes it won't come on at all.
ive replace the actuator the in cabin temperature sensor in the headliner and also the rear ac motor resistor. Like I said sometimes it works perfectly but doesn't work more than it does. Thoughts? Thanks in advance

 

When it's NOT working, pull over, leave engine and AC switched on, and use a flashlight to confirm if the center of the compressor (the drive plate) is spinning as the same rate as the outer pulley. This might be easier to see from underneath....