HVAC controls not working properly

JACKY96

MEMBER
2007 CHEVROLET TAHOE
V8
AUTOMATIC
148,118 MILES

My back A/C control doesn't turn on, but I am able to put up the A/C and down and switch to heat and cool I just can't see the temperature or if it's in max or low blow. The A/Cand heater works great, I just can't see the temperature. I bought a new one and it's the same; I can't see what temperature or what blow it is in I can just switch from cool to heat by the guess.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,772 POSTS

Hi,

This is going to be a tough one. Have you already replaced the control module at the front of the vehicle with a new or used one? Also, let me know if this has automatic climate control or manual.

I started looking through schematics, and there are several pages, so please bear with me. LOL

I will watch for your reply.

Take care,

Joe

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Saturday, January 29th, 2022 AT 8:10 PM

JACKY96

MEMBER
2 POSTS

I haven’t but what happened is that we left our sunroof open, and it rained so we think it got wet, but it works when moving it just doesn’t show anything on the screen. The front one works fine I can see the number and stuff.

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Monday, January 31st, 2022 AT 11:09 AM

JACOBANDNICKOLAS

MECHANIC
109,772 POSTS

Hi,

I have a feeling something may have shorted in the printed circuit board (in the module).

At this point, what I'm going to recommend is to have the can-bus circuit scanned. CAN stands for controller area network. Basically, a few wires tie all the different modules/computers together via a few wires. If there is a code stored related to the HVAC module, this type of scan should identify it.

Here is a link that shows how it is done:

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

Let me know if that is something you can have done. If you can't, you may need to simply try a different module.

Take care,

Joe

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Monday, January 31st, 2022 AT 5:31 PM