"AC OFF" Temperature gauge stops registering temperature.

Tiny
SHEHRY786
  • MEMBER
  • 2008 HUMMER H3
  • 54,000 MILES
Few days back I went on a road trip, 1200 km each way. On my way back the "AC OFF" light came on, the temp gauge dropped down to cold and the AC stopped working. The next day after coming back home, I started the car in the morning, the gauge moved spontaneously and the AC started working. Ever since that day this keeps on happening every now and then. Any help will be appreciated please.
Sunday, October 20th, 2013 AT 3:54 AM

8 Replies

Tiny
FREEMBA
  • MECHANIC
  • 1,152 POSTS
The computer thinks that the engine s overheating and turns the a/c off becasue the engine coolant temperature sensor is gone bad. Here is a guide to help you see what you are in for when doing the repairs.

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

Here is the location for your car (below)

Please let us know what you find.

Cheers
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Sunday, October 20th, 2013 AT 6:49 AM
Tiny
SHEHRY786
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Dear freemba,

Thanks alot for your reply. Will check the coolant asap and report back, haven't had any cooling system work done though. Removed the battery and reconnected after 20 minutes, did not solved the issue. Then I did what you said and bam! The car is fixed and I am back on the road. Thanks I love this site.

Best Regards,
Shehryar
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Monday, October 21st, 2013 AT 3:26 AM
Tiny
MGMESA12
  • MEMBER
  • 1 POST
A/c off and engine temperature gauge is a problem I have on my h3 hummer 2008 as well. I changed my coolant temperature sensor too but that didn't work. I accidentally found out that when I play with the hvac knob the a.C light
Engine temp. Gauge acts crazy causing my a.C to turn off. I realized that I recently left the control knob that controls the air duct flow (front outlet, window air duct, floor air flow) off and my a.C hasn't stopped working since. I am convinced thru process of elimination that the problem lies within the hvac assembly somewhere perhaps the resistor. The problem started after I took my hummer in to gm dealership for blower motor harness recall replacement. Play with your air flow direction knob by leaving the knob in off position and see if you a/c light and engine temperature gauge does not interrupt your a/c. Hope this helps !
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Thursday, May 4th, 2017 AT 3:14 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,598 POSTS
Great addition to this thread! Please feel free to help out on the site whenever it can add information that will help.

Cheers, Ken
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Monday, May 8th, 2017 AT 12:25 PM
Tiny
SHEHRY786
  • MEMBER
  • 3 POSTS
  • 2008 HUMMER H3
  • 3.6L
  • 5 CYL
  • 4WD
  • AUTOMATIC
  • 90,000 MILES
Every now and then the temperature gauge drops to zero and "ac off" warning appears on screen and ac stops working. This has been going on since two months. Everything else seems to be normal, just the car has started driving a bit sluggishly but it unnoticeable and may be related with the oil change which is due also the steering may have become a little bit heavier.
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Monday, May 8th, 2017 AT 12:28 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
If the oil change is due, you should have that done. However, it isn't causing this problem. Have you had the computer scanned to identify trouble codes? Has the engine been running hot? As far as the gauge going to 0, have you checked to see if the temp sensor is working and the wiring to it is clean, tight, and not corroded?
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Monday, May 8th, 2017 AT 12:28 PM (Merged)
Tiny
MGMESA
  • MEMBER
  • 1 POST
I had the exact same issue ("ac off light" engine temp. Gauge inoperable. I had the thermostat replaced and my issue was solved. (It is a defective gm thermostat) that should be recalled. The computer is confused so it shuts down the ac to help prevent overheating; but also causes the engine temp. Gauge to become inoperable. For questions respond to this post.
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Saturday, September 21st, 2019 AT 4:03 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,598 POSTS
Excellent addition to this thread! Please feel free to help out whenever you are on the site :)
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Monday, September 23rd, 2019 AT 11:48 AM

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