On dash it reads A/C off, but this is intermittent, sometimes is on sometimes it's off?

Tiny
KENPEN
  • MEMBER
  • 2010 CHEVROLET COLORADO
  • 3.7L
  • 5 CYL
  • 2WD
  • AUTOMATIC
  • 225,000 MILES
A/C may work for a Month/week or day, A/C off may be there an hour/day or week. Okay, my Engine does not overheat even on 6-hour trips. I have changed the Coolant Temperature Sensor and still Sometimes works sometimes not. A shop has said to replace T-stat (okay) Not sure how that would help if it's not over heating but I am willing to try. Now when the A/C off light is on the Temperature Gauge does not work, when Temperature Gauge works A/C works. Seems like sensor would turn off A/C to take load off engine but why turn off gauge so you can't monitor engine temperature.
Is there something maybe in computer that needs to be reset? Please help.
Tuesday, July 26th, 2022 AT 10:17 AM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,639 POSTS
There is a correlation between the A/C working and the temperature gauge. There is a cluster ground under the front seat carpet I would check. If that is okay chances are the PCM or BCM is going out but to be sure we need to do a CAN scan which is easy. Check out this guide and video to show you how. I have also left you the instructions on how to change both of these parts out in the diagrams below in case they end up being the problem. You can get a CAN scanner from Amazon for about $30.00.

Here is a video to show you how:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

and

https://youtu.be/u-4syLc-ifQ

Here is a scanner link:

https://amzn.to/3o41KcZ

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
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Thursday, July 28th, 2022 AT 12:09 PM
Tiny
KENPEN
  • MEMBER
  • 1 POST
Okay, I hooked up to a scanner and reading P0128 shows up (coolant temperature below regulating temperature) I have had this truck for 7 years. The temperature gauge has always been just below the half mark, weather it 110 out or 10 degrees out and it still shows that when it's working. Question: is it reading a below temperature because the T-Stat may be sticking Open?
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Monday, September 26th, 2022 AT 3:33 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,639 POSTS
Yep, that would be typical, here is a generic guide to help you through the steps and the instructions to change the thermostat out for your vehicle in the images below.

https://www.2carpros.com/articles/replace-thermostat

Check out the images (below). Please let us know what happens.
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Tuesday, September 27th, 2022 AT 12:30 PM

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