I've got a 2000 4.7 4X4 SLT. I just bought some R134A from auto zone and recharged my ac. It is only blowing hot air. I checked the compressor and there is a wheel attached to the front of that, that wheel goes on and off intermittently. Any suggestions why my ac is only blowing hot air. Could I have a bad compressor? Thanks -M

 

the pulley on the front of the compressor should be turning, you should also be able to see the clutch engage and disengage, but it should not do so constantly (it should engage and stay that way for a while, then disengage and stay for a while, then repeat) if its not doing that you either have not enough refrigerant or too much refrigerant you need a proper set of gauges to check both high and low pressure in order to figure out which is the case

 

How much r134a did you add to the system? Is it front & rear AC or with the front only? Like shrpshtr said I suspect you have added either too much or to little to the system since it is short cycling.