Have a 1997 f150 slt 6cyl
Less than 50, 000 miles. Check engine light came on. P1116 came up at parts store and told me need new thermostat. Replaced it. Seemed to work. Cleared code. Drove, check light back on. Same code. Sarted to test engine coolent temp sensor and snaped the top off. Replace the sensor now temp gauge does not register and got code.P0116 and P1117. If I jump the wires for the sensor the gauge moves.

 

what temp is the coolant at? Are both hoses getting warm as they should? you may have a bad sensor out of the pack. What brand did you buy?

 

The little hose near the sensor gets untouchable hot way before the big hose get warm. The bottom hose is warm and tje top hose cool with the truck running 20 minutes. The sensor is a BWD. The better of the two O'reillies had.

 

After the engine running longer. The top rad hose is very hot bottom hose not very hot at all.

 

it sounds like the thermostat is working as it should but if all of the wires look good and the contacts arent bent at the new sensor I am at a loss.

 

I replaced the wiring harness just for giggles. Now the temp gauge is working. But. Now after driving a while check engine light comes on. Get a code of P0118 engine coolent temperature circuit high imput. What is that? I turned on my heater and it does not seem to be blowing hot. The temp gauge does not read hot.

 

Make sure your coolant level is up to the mark. That can result from low coolant.