Want this question answered?
your blend door which cost about $1000-1500
The Avalanche has dual controls for the air conditioning system. One control operates the driver side ac vents, and the other control operates the passenger side vents.
that is the default mode for the hvac, check vacuum line on passenger side of motor, comes for the strut area over to motor, main vacuum hose for system, mine had come loose
== == There are three electronic actuators under the dash: one is for the defroser, one is for the bank of four passenger vents and one ( this is you) sends air to the two driver side vents, the two mid-dash vents and the two rear vents. Either this actuator is faulty, or there's a problem with the electrical delivery system; mainly, the whole climate control panel in your dash (dealer cost: about $700.00).
heater fan broken.
Your need to add more r134a Freon. When the levels are not sufficient to cool both sides the car default sends all the cold air to the passenger side and not the driver's side.
The flap that directs sir to the selected vents is jammed or broken...or the switch that controls it is.
The climate control is not operating for the passenger side. Check to insure the physical controls work, and the diverter vents are opening to let the cool air to the passenger side.
This happened to mine every year for 4 years. First few times it was a hose to the compressor, last time it was the actual compressor that had to be replaced...bought it on Ebay for around $300
prior out with a flat screw driver
In the past on my 89 and 99 Astros. When this happens the small vacuum line that runs from the front of the Driver Side Valve Cover to the HVA System on the Passenger side has been broken. This line runs across the front of the engine and becomes brittle from the heat and can crack or break in two. Best results are to replace the vacuum line instead of splicing it.
your driver/ passenger dual zone temperature switch is bad. buy a new one and replace it. $35 at any auto junk yard. easy fix.