How to Diagnose a PT Cruiser A/C Problemby Alibaster Smith
The air conditioner in a Chrysler PT Cruiser keeps you cool in the summer; but if you don't use it on a regular basis, you could end up with a malfunctioning unit. There are essentially three components that make up the Cruiser's A/C unit: the air compressor, the drive belt and the HVAC integrated control unit. Diagnosing the A/C unit is rather simple and can be done in about 15 minutes.
Open the hood of your PT Cruiser and inspect the belt on the A/C pump. If the belt is broken, obviously this will prevent the compressor from working. However, the belt is a drive belt, so check the entire drive belt on the front of the engine for any signs of wear or deterioration. Check the teeth of the belt. If they are damaged in any way, you must replace them to make sure the belt is driving the compressor properly.
Turn the vehicle on. Turn the A/C on full, and set the fan speed to "high."
Check for cold air being blown into the cabin. If the A/C does not blow cold, this could indicate a faulty compressor or a lack of refrigerant in the cooling lines.
Remove the blue cap on the low-pressure line. The low-pressure line is the only one with a blue cap running out from the A/C compressor to the firewall.
Place the pressure gauge quick-connect fitting over the top of the valve on the low-pressure line.
Open the check valve on the pressure gauge, and check to make sure the pressure in the A/C lines is below the red mark on the pressure gauge. If you have pressure that falls within the green band on the pressure gauge, then the A/C system is pressurized---meaning there is refrigerant in the lines. If you are not blowing cold air in the cabin, it means that the compressor has failed. If there is no pressure or low pressure in the lines, there is a leak somewhere in the lines.
Many times when the compressor fails, there is also a leak at the compressor. So have the lines checked by a professional mechanic; if he finds no leaks, then replace the compressor.