Car Forum World

My compressor clutch is not engaging. I have jumped the low pressure switch, changed the relay and tapped the clutch itself when the ac is on and nothing. The low pressure switch does have power going to it. When i try jumping the low pressure switch it makes my engine rev a little for a second or two. this also happens with it plugged in and ac on and happens around every 15 seconds. any ideas?? thanks for any replies!!!