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

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.

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,690 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

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

KEN L

MASTER CERTIFIED MECHANIC
47,690 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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