Temperature guage not working

[BIGFOOT]

I just replaced the therostat in my 1995 Tahoe 5.7l. Three wires were grounded on the nut that goes on one of the thermostat bolts. I had to replace these.

I double-checked the new electrical eyelets that I repaired and they seem fine, even jumped them directly to the battery neg and still no temperature guage.

Any clues on how to best diagnose this problem?

The other guages all work.

 

[95TwinTT]

I'm going to guess the wire came loose on the sensor. You are looking for a dark green single wire that goes to the sensor. If memory serves, it is on the drivers side head towards the front, near the exhaust manifold.

The other coolant temp sensor has two wires going to it. Those wires are black and Yellow. That sensor is only used by the computer.

There is also a Intake Air sensor that looks like a coolant sensor, but that one has Black and Tan wires.

The dark green wire is the only one involved with the dash gauge. :thumbsup

 

[BIGFOOT]

It was a bad thermostat

95TwinTT:

I realized that the heater barely was putting out heat, so the temp guage wasn't bad, the engine just wouldn't heat up.

First checked for an air bubble that might have caused the coolant sensor to not respond by removing it (it is right next to the thermostat housing on the intake manifold) but no bubble came out.

So all I could figure was the thermostat opens at too low a temp. So I went to an AC Delco shop and for $7 bought a factory replacement, made in the good ole USofA. Problem resolved.

The first thermostat I tried was a Mr. Gasket "high performance" (meaning high flow)model. It was made in China.

Lesson-learned (again) - factory parts are almost always the way to go. Oh, and always buy them from an AC Delco parts store, not a dealer (cheaper).

 

[JP422]

Wow... nice find on the fix... I also agree that AC Delco parts seem to be much better quality than most aftermarket replacement parts. On a side note... I noticed most of my AC Delco parts were made in Mexico! haha.. I'll take that over China.