IAT wiring at ECU
 

I'm doing the switch from the maf to the iat and I want to connect it at the ecu end instead of the maf harness end. After some searching is appears the orange iat wire goes to 2P (red/black?) and the black iat wire to either 2C or to 2D (not sure which).

Doesn't matter what two wires the sensor uses, i mean there isn't a correct polarity. Secondly both 2c and 2d are the same ground at jc-02 according to my diagram.
I just chopped off the plug at the MAF end, soldered the wires and heat shrinked the bare connections.

Yes it doesn't matter which is used for power and ground on the sensor. I just decided to stick with black wire as ground. I ended up using 2P (red/black) at the ecu connector for the orange wire and 2C (blue? have to look at the color again) for the black wire. I used a continuity tester and found these were the wires that went to pin 3 and 4 of the maf/afm plug.

I also found this pinout diagram useful:

http://www.boostedmiata.com/MS/harness_MS_pinouts.jpg