I'm having an issue with my temp gauge not working. It cycles while cranking the engine but then it reads nothing. Would it most likely be the sensor or could it be the gauge cluster? Any ideas:help2:

Easy way to test... remove teh sender's connector (located on the drivers side below the alt...) and ground it to something and see if the gauge goes all the way to max temp. If so, the gauge is fine.

Sender is $14 from AutoZone and it's normally stocked AFAIK. I just replaced mine and that fixed the gauge.

It has two temp sensors is it best to go ahead and change them both at the same time? Are they the same part# or different?

I'm not sure about the 93, I assumed being mechanical injection there was no ECM but I could be wrong.

Only one of the senders controls the gauge on my 94, the other is for the ECM. I'd replace that first to give yourself a good reading and then if you run into temperature-related problems replace the one for the computer.

I'm not sure about the 93, I assumed being mechanical injection there was no ECM but I could be wrong.

Only one of the senders controls the gauge on my 94, the other is for the ECM. I'd replace that first to give yourself a good reading and then if you run into temperature-related problems replace the one for the computer.

Maybe off topic but since you brought it up. Where's the one that controls the gage and wheres the one that's for the ECM?

Maybe off topic but since you brought it up. Where's the one that controls the gage and wheres the one that's for the ECM?


the one for the gauge is in the driverside head, and the ecm one is in the thermostat coolant crossover

I'm not sure about the 93, I assumed being mechanical injection there was no ECM but I could be wrong.


yes there is a ecm, its actually desirable if its from a 4l80e equipped truck as it can be turned into a stand alone controller for that trans in another vehicle

Does anybody have part#'s?

yes there is a ecm, its actually desirable if its from a 4l80e equipped truck as it can be turned into a stand alone controller for that trans in another vehicle

I'm up in Oshkosh btw... bought my fire truck from that guy on 26 right before Watertown :)

The sending unit is called a "switch" in AutoZone lingo even though it's not, TU152. Looks like it's the same for your 93 as it was my 94.

Got the new temp switch tonight or sensor whatever they want to call it. I'm going to ground the gauge out tomorrow to make sure it is good & the install the new temp switch. This should fix the issue of the gauge not giving me a reading. Is there something else that needs to be check that could be causing the issue?

It will send you in the 50/50 right direction.

Ground no result = guage/cluster problem/ wiring problem

Ground good result = bad CTS (Coolant temp sender), not be be confused iwth Engine Coolant Sensor(for da puter)

make sure the contact in the plug is decent, i had a ton of issues with mine as half the time it did not make a good contact, i had to stick a thin probe in there to bent the metal to make contact again and it works fine now.

It was the temp switch. Check the wire & gauge & both of them were fine & also checked all of my grounds & they were fine. I installed the new temp switch & gauge is working like it use to. Thanks guys

I have the same problem, replaced both sensors and no help. The guage only moves about one notch when engine running. With the engine switched off but ignition on, guage reads about mid way. strange. Shorted out sensor and guage does move all the way up. Any suggesstions?

I would trace the wire back to the gauge to make sure that there is not a short. Also check the gauge out.

I would trace the wire back to the gauge to make sure that there is not a short. Also check the gauge out.


his gauge works as he grounded the wire and it went full hot, its a bad sender, the connection in the weatherpak connector or his motor is running that cold and he needs a thermostat.

Thanks guys. looks like I'm down to wiring or the thermostat. eighter one is a nightmare on a 2001 GMC Savana 3500 Turbo D.