im having an on going issue with my temp gauge not working. at times it reads fine but then will all of a sudden quit reading, wich then causes the "ac off" to come on the dash and the ac quits working. what could this b? sensor? faulty temp gauge? please help i have a one year old daughter and it sucks when the ac shuts off while shes with me. i live in texas so its HOT!

 

perhaps your coolant temp sensor or wiring is bad? I would check the temp sensor wire plug - corroded or loose could cause it.

temp sensor location links:

https://www.hummerforums.com/forum/h...ocation-26907/

Hummer X Forum • View topic - Temperature sensor location on 06 H3

Could be any number of things, after checking the temp sensor wiring I would get a code scanner and see what it says - they are cheap - $20 or less - can get at local auto parts stores or on amazon:

 

The temp gauge gets its reading from the sensor. The PCM gets its actual temp input from the same source. The PCM does not pay any attention to the temp gauge itself, the gauge is just an idiot light with a needle for driver information.

The "AC Off" in the DIC is from the PCM as a default when it looses temp input (having no way to monitor actual temp, it shuts off the AC to avoid a potential overheat) and it skips by the first "ENG Hot" message you would normally get. Check for a stored code. Seems likely you have a faulty temp sensor, or a bad connection to the sensor in the harness.

 

Appreciate the info I will look into it.

 

I have the same problem. However, I changed the Sensor out, but the Temp. Gauge is not working AND I still get the error code for the Coolant Temp. Sensor.


Any ideas?

 

Bad connection to the sensor in the harness, frayed wire, bad connector itself, and last, a bad replacement sensor.

 

I had a mechanic conduct a continuity check on the wiring. No problems. Checked ecu. No problems. New sensor put in. Got the code.

I will replace the sensor with an oem one. The only place local that has them in stock is Pepboys. So I will order one from dealer and see if that fixes it. Maybe Pepboys brand is faulty.

Could the p0118 be associated with the thermostat itself going bad? I remember the thermostat gauge bouncing to half way then to bottom out on many occasions.

 

My gauge would do the same thing, just quit reading, then it would shut the ac off. Changing the temp sensor didn't do anything, changed the thermostat and after a day to let it reset itself everything worked like it should.

 

Here you all go, hope this helps.
2006 Hummer H3 Thermostat Replacement:

 

Did you get the same P0118 code?
Was it a messy swap out for thermostat?