Looking for some help.
​I have a 2000 DeVille DHS and the front blower isn't working. The control lights up I can hear the acuators working when I change the level but no heat or AC or front defrost. The back works fine until I press the front defrost button which cause the rear to shut right off.

I'm thinking there may be a short somewhere or maybe need to replace the control unit. Anyone having or had similar issues that can offer me any help?

 

I would check to see front blower motor is getting voltage. When you manually change fan speeds do the indicator change to indicate the request?

 

When I disconnect the the harness and check the voltage it is steady at 12.4 for both black and purple wires no matter the fan speed. The rear works when I turn the front on and I can hear the rear blower running and barely feel anything from the front vents. There no change when I disconnect the front blower motor still barely anything from the vents so I don't think the 2 are related.