I just installed a new Temp Sending unit in an attempt to get my guage to reflect the engine temp. The Temp guage did raise a little when the engine warmed up-but the guage needle does not get to "cold". Any suggestions? tkx philv

 

I know on the 4.9 motor, there are two temp gauges,

one on the top of the block near the thermostat housing,

and one on the bottom of the block, on the passenger side,

somewhere near the exhaust manifold,

 

I'm having the same problem with my 1989 F250 5.0. This year I added a new water pump, new ECT sensor, new temperature sending unit, new thermostat, new fan clutch, new heater core...basically everything in the cooling system but the radiator, since that was new in 2010, and was in great shape. The gauge barely moves, and has yet to hit the lowest line on the gage...but it does move slightly.

My next move this Spring will be to add a mechanical gauge to the truck. These dash gauges aren't gauges at all. They're basically dummy lights with a needle that registers electrical resistance. I much prefer mechanical gauges, as they don't lie about what's really going on. I'd like to add a mechanical gauge and retain the crappy dummy light type gauge for aesthetics. If I could get both to work properly, I'd be most happy.

 

On the 4.9, there is a temperature sender and a temperature sensor.

The sender is located on the passenger side of the block, near the top. This is in reference to only the dash gauge.

The sensor is located front of the block, above the water pump.

If you find there is very little movement, it may be useful to pull the cluster out and physically check the needle of the gauge. That's also a good time to check the resistance between the sender and the harness plug for the instrument cluster.

I've done this several times and also ohmed out the cluster itself to verify the integrity of the circuits.

 

^what he said. Did you ground out the sensor wire to check gauge operation? If the needle doesn't go to hot then the wiring or gauge is bad.

 

Thanks for the input. I will pull the cluster and ground out the sensor--after tomorrow's football games. Phil