i overhauled that 5.2 and everything works fine other than the check engine light is on,i put my scan tool on it and it says "engine coolant temperture circuit high input" put a new temp sensor in an stays the same....any ideas?

 

Did you reset the pcm(erase the code)?

 

What year truck, and how many pins on the temp sensor?

 

i erased the code an it comes back on,its a 1999 2 pin

 

Ok, you only have one sensor then.

Check voltage on the pins, see what you get.