I just bought an 89 F250 with a 5.8 liter. The truck runs strong, but I noticed that the temperature guage doesn't work. I replaced the sensor (the one with a 2 wire connection near where the hoses enter engine) and still nothing. When I was searching for a part number online for that sensor before I bought it, I notices that there were two listed on most sites- one with two wires (the one I bought) and another with just one (green) winre connection. As I was replacing the one I get, I noticed another sensor with just one green connection.

Is the second a coolant sensor as well and if so, could that be the problem?

Thanks!

 

The one wire "tempurature sending unit" is for the gauge only, the other one is for the computer. Take the wire off of the sending unit and ground it to the engine or a bracket, go into the cab and turn the key on, if the gauge goes full then chances are the sender is bad, if it stays down then it's a dash or wiring issue. Good luck.

 

That was it. I grounded the wire, the gauge responded. A quick trip to a local auto parts store, $11 and 10 minutes later, the gauge works fine.

Thanks!!

 

Your welcome, thanks for the update.