Heater issues

[sr3bud]

I have a 99 K1500 Suburban with front and rear heat/air, the front heat is cooler than the rear.
I have replaced the actuator and no change, while the actuator was off I rotated the piece the actuator controls and the heat was great, but when the actuator is installed it's cooler than the rear

 

[SnowDrift]

Is there a module that controls it in the rear? Those can fail also, aside from the actuators.

 

[sr3bud]

The rear works fine, it's the actuator in the front that's not not turning all the way. When I removed the actuator, I was able to get good heat up front.

 

[sr3bud]

The rear works fine, it's the actuator in the front that's not not turning all the way. When I removed the actuator, I was able to get good heat up front.

The actuator is new and functions properly