I was told the ac compressor clutch will not engage if there is no refrigerant in the system. is this true.

mine is currently not engaging when ac is put on but I know there is now refrigerant so if the above is true my first cheap step/fix will be to charge it. Thanks

 

There's a pressure switch on the top of the receiver/dryer that will not let the compressor engage if it detects too low a pressure in the system, ie if your refrigerant has leaked out. It's designed to prevent damage to the compressor which could result from oil not circulating in the system in a low pressure situation. When you charge the system you will typically want the compressor to engage-quick fix is to bridge the connections on the pressure switch.

 

Yes, this is a true statement. Also, during the winter, when the temperature goes down to a certain temperature near freezing point, it will also not engage as well to prevent compressor damage.

 

Very True Statement... With the car running and the Compressor unplugged, you can run 12 volts to it with a jumper wire to make sure the compressor is not bad. If the middle of the compressor (clutch) starts to turn, then the compressor is likely fine and just low on 134a... Just a little test before you go by a bunch of refrigerant.

GOOD LUCK!

 

Both too low on refrigerant or too much refrigerant (over charged) could cause clutch not to engage. Pull out the compressor 12v power plug and jump it with a direct wire from battery positive pole, if clutch engages, then your compressor is fine.

 

This thread is full of win statements