fast idle A/C switch/sensor

[dmassey]

When I turn the A/C on, the idle does not increase to compensate for the extra pull on the engine. Is there a sensor/compensator that controls this? If so where is it? I have a 94 xlt 2.3.
Thanks,
Danny

 

[Pengy]

The idle air control motor automatically adjusts engine speed to idle around 750 (if I remember correctly) no matter what load you put on it. It does not go into a fast idle mode with the AC on.
If your IAC motor had a problem, your revs would be too high and causing a check engine light.

 

[dmassey]

The idle air control motor automatically adjusts engine speed to idle around 750 (if I remember correctly) no matter what load you put on it. It does not go into a fast idle mode with the AC on.
If your IAC motor had a problem, your revs would be too high and causing a check engine light.

Thanks Pingy. I replaced the IAC a while back due to the idle being too low which corrected that problem. A few years back this happened so I dixconnected the TPS, reset the idle then reconnected the TPS and all has been well but now the idle has crept back down agagin. I reckon the computer is showing its decisive muscle.

 

[adsm08]

Yeah, the computer does it's thing to keep the engine idling at the proper speed.

If you listen really close when you hit the brakes with the A/C on, you might be able to hear the click of the compressor disengaging too.