Quote Originally Posted by twostep1n2 View Post
I think what your asking is are there two idle air control motors. There is only one. When the ECU sees the AC on it sends out a signal to the idle air control to raise the idle to help with the increased load on the engine when the compressor is running. If you have an erratic idle during the time when the AC is on it maybe due to the IAC needing cleaning. Remove it from the throttle body and clean the carbon off cone end with carburetor cleaner. Also clean the throttle body were the motor goes in to. See if that helps. It doesn’t cost much and can't hurt
Well done buddy, that is the answer i was looking for

So my thinking was kind of right!..it is the ECU which detects the extra load on the engine and raises the rev's (via the IAC) to a higher level.

A further two points.. I have already given the IAC a very good clean (the cone pintal and the whole throttle body) bare in mind, my motor has only done 37K miles and it all looked very clean anyway!!

Secondly, when stood at idle, the Revs increase to 1700 when the A/C is on...this seems way to high for me?..
..Furthermore, when driving along, if i am slowing to a stop and the A/C compressor kicks in, this causes the revs to rise far to much and the car momentarily surges forward ....this can be a bit unnerving if you are only feet from the car infront

Questions: Why do the rev's increase so much when the A/C compressor kicks in? And if it is the ECU which determines this, how can i stop it?