'95 Sierra... AC compressor clutch cycles on & off (engages - disengages) every 2 to 3 seconds when AC -or- window defroster is turned on. Could this be due to a low freon charge? Or could it be a bigger problem? Thanks...

Mine does the same thing. When AC is on it is supposed to cycle depending on how much it needs to in order to cool the air. I don't understand why it does it in the defrost mode, though. I haven't started troubleshooting it. Have you checked the freon level in the AC? try that. I know mine leaks slightly so I have to refill it about once a year.

A/C on during defrost is normal. It helps dry out the air in the cab to reduce fogging. cycling on and off may indicate low freon. there is a refill with lube and stopleak at walmart you can do on your own. If you dont want to do it, take it to a trusted shop and have them do it.

thanks 70. saved me a ton of troubleshooting chasing a non-existing problem. I refill it myself and will use a stop leak freon next time.

Thank you both... I'll get the freon level checked. Got'a be it... Here's keeping my fingers crossed...