S13 blacktop IACV question

[S13alldayyo]

I know there's 2 parts to the IACV I forgot there separate names , but anyways there is 4 wires on the plug, I want to know which one is the one that kicks up the idle when you turn on the ac because mine is not kicking on, I'm going to wire it myself to a switch by the compressor, any help
Will be appreciated , thanks!


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[zombiewolf513]

Youre refering to the AAC portion of the valve i believe

[jakemkz]

Hi,
The manual describes the AAC Valve and FICD solenoid and their wiring on pages B-137 and B-138 of the 1991 SR20DET engine manual. I believe the FICD solenoid is the component you are referring to (FICD = fast idle control device). Pins 1 and 2 (the two closest to the tab of the IACV connector) control this solenoid. The high side (pin 2) is connected to the A/C relay and the low side is connected through a diode to the "外気" switch and pin 45 of the ECU. 外気 means "open air" which I believe is referring to the circulation switch on the heater/AC control panel, although I am not completely certain. If your AC compressor is working but the FICD solenoid is not check pin 2 for 12v with the AC on and then unplug the IACV plug and check for continuity between pin 1 on the plug and ground. If both of these are OK then the solenoid is probably not working properly. With the connector disconnected measure the resistance between pins 1 and 2 on the IACV. I don't know what the coil specifications are but I would guess something in the range of 10-1000 ohms, if there is no continuity between pins 1 and 2 on the IACV your solenoid may be broken. Good luck with your fix.