2006 GMC envoy Denali AC
Car AC system will only go to extremely cold or hot
no intermediate temperature and blower is still
blowing out at full speed
My son had the same problem in his 2006 GMC Envoy XL. I had to replace the Blower Motor Resistor. It's found behind the glove box. It was fairly easy to remove the old one and splice in the new one. I think the hardest part was maneuvering my 6'2" frame between the seat and the lower portion of the dash.