91-94 temp guage not working? FYI Here's a fix...

[Jason94sport]

So your temp guage isn't working on your 91-94 Explorer. You replaced the thermostat thinking that was the problem, & it still reads cold. Have you replaced your engine coolant temp sensor? If not I'd bet your's is bad. Mine was. It's a $18 part & takes a whole 5 minutes to replace. It's located right next to the thermostat housing on the front of the engine. It's real easy to get to. It has 1 little wire coming out of it. Once replaced the temp guage lit up like a christmas tree, & all is good with it.

 

[Fred Garvin]

Yeah, I had a 90 Ranger once--the oil guage started jerking around, so I replaced the oil pump.

THEN, I changed the oil pressure sending unit and the problem went away.

On my 98 Explorer, the oil pressure "appeared" to be going down, so I replaced the oil pressure sending unit, and that fixed it. The oil pressure sending units are usually more inaccessible than the temp sending units though.

 

[MrShorty]

One thing to watch out for. Some will have separate dash gauge sending units and EEC-IV engine coolant temperature sensors. If you ask for the ECT, you will get the EEC-IV sensor that doesn't have any effect on the dash gauge. Having two separate units can allow you to use the EEC-IV ECT sensor to check the operation of the dash gauge sensor. Just put a volmeter across the ECT and compare the two. If the ECT signal and the dash gauge parellel each other, then the fault lies in the cooling system. If the ECT signal and dash gauge don't appear connected, then one of the units or its related circuitry has a problem. This can be used, not only for diagnosing a non-functional gauge, but also for checking a gauge that reads consistently high, or for checking on an erratic or "swinging" gauge.