Coolant temp sensor
 

Hey all I have an 01 Blazer. I have read posts and read posts still cannot figure out my temp sensor. It seems I may have an older engine as I have 2 temp sensors, 1 in the drivers side head and 1 in the t-stat housing. The 1 in the head is not plugged in, nor can I find the connector. The one in the t-stat housing works the gauge. Can someone clear this up for me since everything I've read said the 1 in the head works the gauge. Thanks for the info in advance.

IIRC, 96 & newer engines only have one ECT sensor, and it's near the thermostat. Data is sent to the PCM for engine controls, and is shared with the BCM, (Body Control Module) which supplies the instrument cluster with engine data.

one can control the gauge and or can be for computer feed back
one can be for the idiot light

My '01 only has one in the head. The used lower intake manifold I got had one near the tstat. I didn't realize it and plugged the connector into the ECT sensor neat the tstat. it worked just like when it was plugged into the one in the head. I even used the same connector for both sensors. It was long enough to reach.

Thanks for the clarification.

My '95 has two sensors, IIRC. The one in the driver side head only goes to the gauge. The other, near the t-stat goes to the computer.

Correct, '95 does not have a BCM.