Possible Air Door problem?

[RonnieT]

I cant ever find the solution that fits my problem on this.

I have a 2000 GMC 1500 4wd ,3 door, 5.3 engine

150,000 mile always maintained.

Every since I owned it, 9-10 years it has had an air door problem.

The problem is only in winter time. I never notice it in summer with the AC on.

I like my hot air to blow on my feet and I like a lot of blow.

I cannot get enough hot air coming from the vents on the drivers feet or the passengers.

I can when I get it up to the defrost or the AC face vents but that is not desirable with hot air.

2 winters ago I even stuffed some red rags in the the outlets under the seat that help the rear seat passengers but still don’t get enough air.

Fan works great on all speeds,

water pump was changed this summer all pulleys , belts , thermostat all original equipment , heater core changed 4 years ago cabin air filter is changed hoses are hot and the hot air feels good just need it to blow.

I am sure it is an air door actuator but which one?

The one easiest to get to is the one on the drivers side bottom with the covers removed I can see it working but is it going far enough ? I do not know.

Any hints or tricks or I don’t mind changing a actuator if I knew which one .

The dash has never been apart , only the heater core and it was doing this before then. I hear no noise when I change the heater AC controls.

anyone have a starting place it is fixing to get cold again.

Thanks

Ron

this is the type of heater control I have see picture.