The one with the yellow and black wires. Does it connect to this plug on the thermostat housing? I tried pushing it in for a couple of minutes but it wouldn't connect.. Maybe I have the wrong plug??

 

Someone replaced the pigtail for the coolant temp sensor. Both wires are black because it's a generic replacement. Since you can trace it back to where the wires are color coded (yellow/black) you know that it's a coolant temp sensor circuit, and that sensor on the water neck should be the right one. But there's no guarantee that the pigtail they crimped on there is the right one for the sensor.

 

Wrong pigtail

Gray body means IAT, CTS is black. Look closely at the sides and compare to the ones in the sensor

https://www.thirdgen.org/forums/ltx-...erchanges.html

 

dang...
ok. just to make sure. would this be the right one?
http://www.autozone.com/autozone/par...342421_0_6643_

 

Thatd be the one

FWIW, grab one from a JY for pennies on the dollar compared to that

 

Thank you Pocket. (and for that link too, nice.)

 

Just to add a note on wire connections. If you must use butt connectors on sensor wiring, use the type with heat shrink on them. Butt connectors are not sealed and they will corrode causing resistance in the circuit. Sensor circuits are low current and very sensitive to resistance.