What causes the air vents in front to give cold air and hot air at the same time on 2003 Hummer H2

When I turn on the engine i notice that on the passenger side air vent hot air. The drivers side blows cold air. When I shut off the engine and wait an hour it sometimes works properly.

by in Fort Worth, TX on January 22, 2012
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer
ANSWER by , February 07, 2016
its the blend door actuator https://www.youtube.com/watch?v=5lnd8UNcx6M its the same on a cadillac escalade and a hummer h2 i had the same problem