Here is a pic of the idle control on the Z32: Rear driver side of the plenum.
To remove, disconnect the rubber hoses to the IACV, three pain in the a$$ connectors (Air reg, ACC, FICD), undo the four 10mm bolts using 1/4" drive. Note there is a gasket in between. Removing the balance tube will give more room too. Stuff rags btw the firewall below the idle bolts will save you head aches when you drop stuff.
Apply 12 v to the AAC and you should hear an audible click.
Functions:
Air reg is to slowly close as the car warms up with a copper bi metal valve. If this fails, high idle, happens rarely
FICD opens a valve to allow air in when accessories are turn on to increase idle slightly. If this is stuck open, high idle, happens rarely
AAC is controlled by the ECU to maintain the idle value as set in the ECU ROM, it constantly clicks on/off duty cycle to set idle. If this fails, you will be unable to adjust the idle with the adjustment screw. Note that OEM ROM chip is set to approx 650-750 RPM, some aftermarket ROM chips are set as high as 900 RPM.