Your A/C system may have lost its charge of refrigerant, or the compressor may not be engaging when you turn on the A/C, or the blend air door inside the HVAC unit may be stuck in the HEAT position so no air goes through the A/C evaporator.
Before condemning the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).
Find out if the compressor is working.
If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery
(Use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch
If the compressor does not engage when you jump it, the problem is a bad compressor clutch.
If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged. If you Have an A/C gauge set, hook it up and see if the system has any pressure.
If the system has pressure and it blows warm air when turn on AC, you may have faulty electronic blend door actuator.
Saturday, April 10th, 2010 AT 11:27 PM