I have a 1990 f250 5.0 5speed 4x4 and the tempature gauge wont move. When you first turn the key on it goes from cold to a lil before colder but wont budge after that. I have done some thread searching and is there a possibility that there are to temp sending units. One for the gauge and one for the computer. I replaced the sending unit at the T-stat housing to no avail. Thanks Josh

 

I had to get a new gauge out of the junkyard when my old one quit.

 

KineKilla how did you know your gauge was bad??

 

Maybe a bad temp sensor. I replaced mine and my gauge was accurate afterwards

 

Which temp sending unit did you replace? The 2 pin temp sending unit is for the ECU and the single pin sending unit is for the dash gauge.

A simple test to see if your gauge is bad, is short out the single wire sending unit's wire to the engine block, the temp gauge should peg out in hot.
If it does, then that sender is bad, if not, then the gauge or wiring to it could be the cause.

 

I just rolled the dice. It only cost me like $5 and a little time. Also, it wasn't overheating and the fan was kicking on as it was supposed to, so I figured it was just the gauge.

 

Where is the sending unit for the gauge located???

 

Its on the intake manifold next to the thermostat housing. It has the single pin connector on it. The ECU coolant sensor is usually in the heater supply line and it has 2 pins for it.