strange occurance

Are you sure the noise is not coming from the alternator? It sounds like when you put on additional accessories, you are putting additional load on the alternator, which can make noise. In that case it might be time to change the alternator. If it is definately coming from the compressor, the only thing I can think of is that either the extra electrical strain put on the alternator is causing it's pulley to spin less freely, causing possible belt slippage. Or, the alternator is defective, not putting out the right voltage under heavy load, which means the compressor is not getting the full voltage it's suppose to be operating at. I would start with the basics first. See if the belts are tight. If that's ok, hook up a voltmeter to the battery and see if the alternator is charging right. It should be at around 14 volts with no accessories on. Then turn on the A/C and the lights and check the voltage. If there is a big drop, it could be the alternator.

What happens if the compressor is off, and you turn on the headlights? I suspect the problem is the alterntor or electical system and not the compressor.

You are most probably right about the alternator. I just did a cursory look when listening for the sound. I will check the things you mentioned today and post back.

Thank you.

I am sure you are right about it being an electrical system problem. Checking it today.

Thank you.

I'll bet the noise is coming from the alternator not the compressor.

mike hunt

forked wrote:

Alternator bearings.

well you might check the drop in voltage that is going to the compressor's clutch coil... with the lights on the voltage might drop and then instead of getting full voltage(12volts) you might just be getting