regarding IACV troubleshooting..

in the haynes it says when you disconnect the 2p connector the idle should go down drammatically. is this true? i dont see why it should since there is no load on the engine when you do this.
when i disconnect mine, i hear a click down by the egr, but the idle stays teh same. im gonna be checking its voltage next… otherwise i guess its a 220$ part i need to cure that a/c vibration =/

also it says the last step (before replacement) is to have a professional service it. who would that be?