94 Celica A/C

If an idler is missing, the AC wouldn't run. A faulty idler will make noise.

The symptoms you're describing sound more like the idle-up circuit, which increases idle speed when the AC in engaged.

Thank you for the info Ray O. Could you possible provide some troubleshooting tips?

I'm with Ray here, it isn't the Idler, it's the Idle Up Circuit.

An idler is a pulley that has no particular function than to give the fan belt a place to go. An idler pulley can be a fixed position, or adjustable. This depends on where the idler has to be placed, and how much room there is around it.

The Idle Up Circuit detects that the A/C has been switched on, and it increases the engine speed a bit to counter the extra load of the A/C.

I'll try, but....

Can you refresh my memory on what is wrong with the car? When, outside temp, engine hot or cold, steering wheel straight or while turning the steering wheel, etc.

Thanks for the info. When my girl told me about the idler, I was confused as well. I told her that didn't make sense. The car blows cool/warm air at a light and needs to get up to speed (over 50) before it will start blowing colder air. I checked the system as best I could and everything seems to be good. The different pipes get hot/cold respectively, belts tight and compressor seems to cycle on/off as needed. I haven't been able to locate the drier to check the sight gage yet. I hope this helps. Thanks again, Jojo