2001 Suburban: heat in the back, not in the front
So my 2001 Suburban decided to stop blowing heat in the front. Back system still works fine but none in the front. Fans still work and a/c is working, just no heat.
This is what I have done so far:
-hoses are hot going in and out of the heater core so it doesn't appear to be a blocked core
-took out the blend door actuator and put a new one in. Didn't work either. Took it to a parts dealer and we were messing with it. The original actuator was moving, then it stopped moving. Put a new actuator on and it wouldn't move either. Seemed to be sporadic.
-Went to the junk yard and got a heater control from another 2001 Suburban and put it in and still the actuator would not move. (I actually called the dealership about this part and GM won't even allow them to order it for some reason).
What could be the problem? Is it a relay? If so, where the heck is the relay located at? Anyone have the part number or location? Figure that is an easy check. Or could it be a ground issue and if that is it, how big a problem is that because I have no idea how to fix that. Any and all help would be appreciated as I have no idea what the problem is.
This is actually the vehicle my wife drives and she doesn't like to drive around in a ice cold car. And let's be honest, is she ain't happy, ain't no one happy.