Finally had a warm day this weekend and wanted to use the air conditioning but found that it was blowing only hot air. I thought I might be low on refrigerant so I attempted to load a can of freon. However, the A/C Compressor will not engage. I have checked all the fuses and relays...everything appears to be fine there. I attempted to jump the pressure switch with no success and also disconnected the battery cable thinking that the computer would reset. Other than a bad compressor is there anything else that would prevent the A/C compresor from engaging? Any suggestions would be appreciated. Thanks.