I have seen where folks have changed the TSU and/or the thermastat to fix cooling fan shutting off and no temp reading on guage and some were fixed and some were temporary fixed just to start doing the same thing a day or so later.
Here is my Dilemma- Yukon drained battery over night because fans didnt kick off. I check it out and decide to just change both a one time, the TSU and the thermastat. Also checked the wiring and plugs. Results- Never changed a thing. So I decide to unplug the fans and let it idle to see if it warms up even though the gauge stays at 160. after about 45 min of idling with the fan fuses pulled, the truck was hot. So now I know the new thermastat is opening but still no guage movement nor will the fans turn off. I have cleared the code and pulled the cables off the battery for extended period of time. Still no luck. I have a hard time believing that the only thing left is a bad ECM.
Here is my Dilemma- Yukon drained battery over night because fans didnt kick off. I check it out and decide to just change both a one time, the TSU and the thermastat. Also checked the wiring and plugs. Results- Never changed a thing. So I decide to unplug the fans and let it idle to see if it warms up even though the gauge stays at 160. after about 45 min of idling with the fan fuses pulled, the truck was hot. So now I know the new thermastat is opening but still no guage movement nor will the fans turn off. I have cleared the code and pulled the cables off the battery for extended period of time. Still no luck. I have a hard time believing that the only thing left is a bad ECM.