2003 Envoy HVAC Problem - Automatic Controls

I’m having the following problem with my 2003 Envoy’s HVAC system (Automatic Controls). Somedays it works fine and other days it will not work at all. Sometimes it will come on and regardless of the fan setting (High or Low) it will barely blow any air, other times it will blow full blast when set on low. When I change the control setting (Floor, Forward Vents or Window/Defrost) it will take several minutes for it to cycle through and open the correct vents. Other times it will be on and nothing will happen regardless of the settings. Is this a “Mode Door Actuator” problem or the “Control Module” or both? Is there a way to reset the Control Module? I’m not a Technician. It tends to not want to work on the HOT days!!! Help! :frown:

P.S. I found a TSB addressing some of these problems but it is for the 2002 model and GM changed the components for the 2003 model.

Thanks

You need a new Blower Motor Control Module. I have a 2003 Envoy also and recently had same problem. Fortunately, I have an extended warrranty and repair cost me nothing; however, I would have repaired it myself if I didn't have the warranty.

The blower motor is just behind the glovebox which you will find is easy to drop out of the way. Then you will find the control module held by a couple of bolts and an electrical plug in to the blower. You'll have to get the module from a Dealer most likely. It is an expensive part at about $113.

C.B.

Thanks for the info. I'll order that part and do the install.
I'll post on here if it solves my problem.

Thanks for the info C.B.

I had my Dad (Retired GM Emp.) get the part for me .... $61.28 :)
It took about 40 minutes to remove and install unit, plastic cover, reconnect battery etc. It works like it's supposed to now.