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rpmdiag, Tech and Instructor
Category: GMC
Satisfied Customers: 8130
Experience:  Since 1975
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The heat in the back of my Yukon works great. The air in the

Customer Question

The heat in the back of my Yukon works great. The air in the front is luke warm to cold this winter. I have replaced my cabin filters and the airflow increased but still the same problem exists.
JA: Have you checked the coolant level? Have you checked for a leak in the radiator?
Customer: Yes, it is full and both hoses from the heater core are hot.
JA: What year is your Yukon?
Customer: 2001
JA: Are you fixing your Yukon yourself? What have you tried so far?
Customer: I am fixing it myself. It worked fine all winter last year and the AC worked fine all summer. This winter I have only changed the cabin filters because I was not getting much air flow. I have plenty of air flow now but still cold in the front and hot in the back.
JA: Anything else you want the mechanic to know before I connect you?
Customer: NO
Submitted: 9 months ago.
Category: GMC
Expert:  rpmdiag replied 9 months ago.

Hi, I'm Ron and I will be helping you today.
Stand by for a moment while I prepare your answer.

Expert:  rpmdiag replied 9 months ago.

The blend door that services the front of the truck is not changing all the way to heat. It is part way through from cold to hot.

This blend door is inside the heater box under the dashboard.

Thanks, Ron

Customer: replied 9 months ago.
would it be an actuator problem? Or a controls problem in your opinion?