2001 yukon xl Heater issue

[sleddinskeeter]

Ok well heres what I know.
My wife calls and says the heat in the front of my car wont work it blows cold air. But the rear Blows warm air 83 degrees in fact I checked with laser temp finder. so I go outside let the vehicle warm to op temp and fire up the fans.

Test results are this
front air vent temps defrost 40 degrees
rear air vent temps 83 degrees
heater hose at t supply 130 degrees
heater hose from cab return 60 degrees??

So I think possible causes are: Air door in th front stuck or sticking
Or plugged heater core
ANY Ideas ?? thanks

[sleddinskeeter]

Well taking it to a mech today Thanks anyway

[sleddinskeeter]

Backflush Badda Bing Badda boom Good ta go