IIRC most have two sensors (G2 and G62) one is ecu the other is cluster. don't recall which is which.
If not, the ECU usually sends the temp to the cluster via kline or CAN
Since you are having other issues communicating with the TCU and Airbags, I'd say your kline or CAN bus are screwed up somehow (if your car only has one temp sensor)
The one connected to the ecu was easy to find using wiring diagrams, but I cant really find the one going to the cluster. I do have two sensors, one fat and short (brown), the other thin and long (black) on the sensing side (i'm not 100% sure which is meant for which, but pretty sure that the black one is for ECM)
I had to go from, IMMO2, possibly even IMMO1, car to IMMO3 so the whole interior harness had to be cut up, so I might've missed something, but as far as the engine wiring diagram goes, I couldn't find where to wire the second sensor.
Also, I would think that there would be issues communicating with the TCU (if I got it right, that' Transmission Control Unit?), because it's a manaul car now and there is none, I remember reading something somewhere about how you can disable it (I THINK it had something to do with ECM and cluster not being paired), hoped would get rough directions
If not, I'll look around when I get more time.