hi,
my temp gauge has been acting up for over a year now on my 05 Monte Carlo LS 3.4. it comes and it goes. i've changed the temp coolant sensor twice, the thermostat (autozone) and the temp coolant sensor connector. nothing fixes it for very long.
i thought i had it fixed last week when i installed the thermostat last week but it just stopped working this afternoon on the way home from work.
when the temp gauge bottoms out i lose Air Conditioning and my fan stays on. the fan stays for a minute or so even after i've shut off the engine. i know first hand that the stepper motors in these gauges go out because i've replaced my speedometer stepper motor a few months ago. but if it was the motor in the gauge i don't believe it would shut off my aircondtioning or have an affect on my fan would it???? is there a relay or fuse or perhaps a bad ground causing this? or maybe i need a GM thermostat? please help because i'm so tired of fooling around with this.

 

could something be wrong with an Air Conditioning relay causing gauge problems?????

 

I had the same problem it turned out to be the thermostat. Did u check the spacing in the thermostat before u put it in

 

I had a 2001 Impala with a 3.4 that the temp gauge bottomed out , fans stayed on, I changed the thermostat and bleeded the coolant system.
After that I had no problem..

 

i've never changed a thermostat so i'm not sure what you mean by "" spacing of the thermostat?" It was very hard to get to. i had to remove the throttle body and still could'nt get a good look at the thermostat housing. i did change my coolant when i changed the thermostat. i'm pretty sure i bleed the air. would any air in the systom eventually work it's way out through the expansion tank? how would i bleed the air once the coolant is in the radiator? could i just open the bleeder valve and maybe turn on the engine to accomplish this?

 

sorry for that my above statement is a bit confusing. I did change the thermostat but could'nt get a good look at the housing cause becuase of it's cramped location. it perhaps may not be seated properly. i don't know about "spacing" thou. not sure what it means?

 

Yah don't quote me on this but I think it was suppose to be 1 1/8 inch space from the bottom to the washer. But like I said don't quote me maybe someone else can confirm. Hopefully this helps

 

My 01 Monte Carlo SS has been overheating constantly previously, ive changed radiator fan new thermostats and flushed it out. It helped for a little while, had to replace thermostat about every 2 or 3 months until I just took it out and kept it out, it stopped running hot the temp gauge worked fine for about 6-7 months. Now the temp gauge just doesn't work at all. And im now getting a code that reads: thermostat temp is under regulating temp. How do I fix this and how bad is this?

 

just replaced a coil pack due to misfire, car is running like new and now the temp gauge works again.

 

Well that's cool!! Two birds with one stone