Hello folks! New to the forum. Recently bought a 2001 Ls blazer. Was about to flush/ fill the coolant, replace the temp sensor and thermostat. I noticed there's no wiring harness attached to it. Seems pointless to have a sensor with no source of power. If there should be a harness where will it be routed from? Picture attached

 

I would look around for a wiring schematic on your 2001 . Try using the search options .

 

must run like crap without it hooked up