Hey I have a 97 3.4L manual trans 4Runner and I'm pretty sure that the wiring for my IAC valve is bad, I just don't know what wires to test on the ECU end. I've been searching for a diagram but can't find one anywhere. I'm just wondering if anyone has one or any advice on tacking one down. Any help would be greatly appreciated!

 

First off, have you seen this excellent video on the IAC: Next, up in the sticky links you can find the service manual for 96-02 4runner. Normally you would find what you are looking for under the "Engine Control" section. Problem is that this manual is not entirely accurate for your year, and does not even show the IAC as far as I can tell. Trying to get the proper ECU pinout and wire colors can be a challenge, but maybe the attached is what you need:

The first shows exactly what you see when you look at the ECU connector behind the glove box. It works for a '98 so maybe it works for a '97. The wire colors and pin assignments may not be 100% accurate. Note that in yotaspeak, "L" is shorthand for blue color. The second actually shows the IAC wiring on ECU connector E9 pins 22, 23. The colors may or may not be accurate. Note that on the 2002 wiring, these same ECU pins would be for the knock sensors. You can check continuity from the IAC connector to these ECU pins to make sure.

 

I have seen that, he makes great videos! And yeah, I tracked down a service manual but after reading through the whole thing multiple times (although it has information on how to confirm that the valve itself is functional with all the necessary resistance values and all that good stuff) it doesn't appear to have a diagram of where the wires from the IAC plug into the ECU...
Which is weird because it has that for pretty much every other system and that's how I was able to test everything else and confirm that it's my IAC.
It's a brand new IAC and I know it works it's just a problem in my wiring harness.
I've known that for a while and it been a mind numbing process of trying to track down the dang diagram (I'm a wildland firefighter and I was even searching the web for it on the rare occasions we got service) so I appreciate the help!
I think I can use the first link you shared and test all the pins that have operating conditions based on the idle and hopefully find the right ones.

 

Yes, some of the notation on the diagrams is a mystery. If you just clip on each wire in the (disconnected) IAC connector and probe all the pins on the first ECU connectors (E9 and maybe E10), you should find which pins are used. It is unlikely that both wires are bad. Once you find the pins, you can unplug E9,E10 and make sure the wires aren't shorted to ground or each other, then repeat with E9,E10 plugged in to make sure the ECU pins aren't shorted.
So how is the vehicle misbehaving that you think its IAC related?