Hi Linden,

From your description it is obvious you DO have an IAC, and that it is working in the fully-open and fully-closed position. However, it's more important that it be working (and can be controlled accurately by the ECU) in the partially-open position - since that's where it spends most of it's life in. That's what I found with mine: it worked fine when I shorted the extreme connectors to ground, but was still causing a high idle. I opened it and cleaned the commutator and spindle, and the high-idle went away (see this post). The above thread also has a lot of valuable IAC info from other more-experienced members.

By the way - when you say 'my IAC dosn't work' - what exactly do you mean ?

Another thing to check before you open up that IAC is if you are getting any voltage at the IAC-connector end. If the IAC connector-rubber-boot is split like mine is, you can check this without unplugging the IAC connector since you have access to the back of the connector-terminals. If it is not split, remove the connector and check that you receive voltage between center and extreme terminals with the engine running.

If you do not get any voltage, you have a problem with the wiring. If you do
see voltage, you could still have a wiring-harness problem if one of the wires are shorting with ground somewhere (since that's sufficient to fully open or close the IAC). Make sure you check your wiring for crumbling insulation and shorts before you open the IAC. The way I did it was remove the ECU connector and check for continuity and possible-shorts of each and every wire. I also checked the following at the ECU connector end to verify that all signals were getting through to it:

- plugged the IAC in and measured the coil resistance of both coils
- checked coolant temp. sensor resistace (verify it matches sensor resistance)
- checked working of the TPS switch
- checked continuity of the CO and idle-setting test-leads
- AMM resistance (verify it matches resistance at AMM end too)

Let me know how it goes. Also explain in detail what your IAC problem is that leads you to believe it dosn't work.

Noel