A/C blows warm and Climate Control Panel does not light up

ERVIKINGO

MEMBER
2003 CHEVROLET AVALANCHE
5.3L
V8
2WD
AUTOMATIC
145,000 MILES

Gas level/pressure is correct, replaced pressure switch, compressor cycles normally.

The air blows warm (perhaps dampers are blending in heat when all I want is cold) and now Climate Control (auto dial zone) won’t light up.

When I unplug the control panel and plugged it back in, it lights up for less than a second.

Perhaps related, some months ago started having alternator whine on right rear speaker.

Have reset system (battery disconnect 30 minutes) checked all fuses and relays in the truck.

Thoughts?

7 Replies

KASEKENNY

MECHANIC
18,907 POSTS

This could be a blend door issue but we should start with what you are seeing so that we can be sure to be on the same page.

Can you get a picture or quick video of the HVAC so that we can make sure that I understand what you are seeing?

However, the best thing to do is check for power at the module to make sure you are getting proper voltage on all the circuits that are coming from fuses and the illumination circuit?

https://www.2carpros.com/articles/how-to-check-wiring

Then monitor the voltage on the temp door circuits and change the temp. The voltage should be moving. If it is then the blend door is the issue.

However, we need to make sure about this because the module may be the issue and not the actuator.

I attached the wiring diagrams below which will help with this.

Let's start with this and go from there.

Thanks

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Wednesday, May 18th, 2022 AT 8:52 AM

ERVIKINGO

MEMBER
4 POSTS

Thanks for looking into my issue! As you can see on the video, I start the truck and the display blinks and goes dark. Buttons (on/off, fan speed, recirculation) work. I hear the compressor click and the dampers seem to work (at least the recirculation one).

Sorry for wind noise but that is air from the vents.

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Wednesday, May 18th, 2022 AT 10:17 AM

KASEKENNY

MECHANIC
18,907 POSTS

Do you have dual zone temp control? I think that is the only option on this vehicle so if that is the case then I suspect the controller is the issue. It is highly unlikely that there is an issue with both blend door actuators.

However, I would suggest just accessing the actuator and change the temp and see if you can feel it moving.

https://www.2carpros.com/articles/replace-blend-door-motor

See the attached info from the manual on the passenger side actuator as I think that is easier to access.

If it is not moving then the module is most likely the issue which would make sense based on what you are seeing with the lack of illumination.

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Wednesday, May 18th, 2022 AT 1:52 PM

ERVIKINGO

MEMBER
4 POSTS

Correct Dual Zone. I wonder if the controller is not sending the correct signals to the blend valves etc. Losing the display is a telltale of perhaps a larger issue.

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Wednesday, May 18th, 2022 AT 3:47 PM

KASEKENNY

MECHANIC
18,907 POSTS

Correct. That is exactly what I am suggesting. Since you have dual zone temperature it is highly unlikely that the actual actuator is the issue. The way to confirm this is to check the voltage coming from the module on the temperature doors to find out if they are changing which will confirm this.