HVAC issue, blower doesn't work at all

[Wagnasty]

So my 2003 Yukon Denali sat for a while with a dead battery. I finally decided to replace it. After that neither front or rear blower motors worked.

The a/c would cycle if you moved the temperature control knob and if you were driving down the road with recirculation off the air from driving would come through the vents in the selected zone.

Then one day the rear blower started working. I didn't touch anything, it just came on. Great, but the front still doesn't work.

I replaced the resistor, the blower motor works when hooked to a 12v/gnd. I have 12v at the blower motor, and I have it and a good ground going into the resistor.

I figured it was the digital climate control itself, but I changed it also with no luck. I've done the relearn process 4 or 5 times, fuses good, and I'm really at a loss.

Is there something else that controls the blower motor? Its got to be something that commands a ground signal. Even the continuity from the signal wire on the resistor checks out.

 

[Wagnasty]

Anyone have any ideas here?

 

[ivin74]

Have you checked the actuators? I would start there, please see video

 

[Wagnasty]

As stated the temperature will change when you command it to. And you can select floor/dash/defrost.

Only thing that won't work is the blower itself.

 

[Fless]

So my 2003 Yukon Denali sat for a while with a dead battery. I finally decided to replace it. After that neither front or rear blower motors worked.

The a/c would cycle if you moved the temperature control knob and if you were driving down the road with recirculation off the air from driving would come through the vents in the selected zone.

Then one day the rear blower started working. I didn't touch anything, it just came on. Great, but the front still doesn't work.

I replaced the resistor, the blower motor works when hooked to a 12v/gnd. I have 12v at the blower motor, and I have it and a good ground going into the resistor.

I figured it was the digital climate control itself, but I changed it also with no luck. I've done the relearn process 4 or 5 times, fuses good, and I'm really at a loss.

Is there something else that controls the blower motor? Its got to be something that commands a ground signal. Even the continuity from the signal wire on the resistor checks out.

I'm wondering if the digital HVAC head needs to be programmed to the vehicle, or at least be a used one out of a vehicle with the same options. Did you get a new, or used, one? If new, did the instructions say it required programming?

 

[Doubeleive]

does the blower motor resistor have power going to it? if it does then it might be defective, if it does not have power going into the resistor then you may have to trace back from there or double check your fuses.