Heating and cooling control doors in dashboard. How to repair and replace. doors do not open or close or are stuck open, no heat in the winter and no cooling in the sumer.

There are 2possibles ,1. The heat / cool slide control is defective, it is not possible to repair. Most likely the servo motor that opens and closes the air vent that gives you heat or cool is stuck. Open your glove box and you will see 2 rubber tabs that hold the door at the open and down position. Push down on your glove box door until it swings all the way down (this wil be past normal open) up inside you will see a metal rod affixed to a arm that pivots via the servo left is full vent(cool) right is full heat. Push your hot/cold heat selector and see if it moves. It may not be moving its full extension. If your not sure push it right and you should get heat push it left and you should get cool check YouTube this is a common problem for this era of Buicks, good luck Bret

Presuming your car is fitted with the automatic heating/cooling system.
There is only one fan controls the heating/cooling system the distribution from this to the various vents is controlled by a series of electronic flaps which open or close dependent on the temperature selected at the control unit.
If the motor is running and the drivers side is receiving cooling it may be a problem with the control unit or a flap has stuck open.
Replace the control unit first as the flaps are a citroen job.
Control unit is the bit with the temperature displays etc.

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Locate the heater hoses and feel for temperature.Should be warm to the touch.
There may be an external heater control valve next to the firewall that is either vacuum or cable controlled.
the lever on the side opens and closes: warm coolant going into the heater core,inside the cab. If the valve is stuck,no heat.
If the vacuum to the valve is ZERO,it should open.
If the heater control vacuum hose is leaking air,you should get hot air ALL of the time.
people in the winter want heat NOW. Bypass the heater valve,under the hood with a section of copper or plastic tubing.
Even if the heater core is partly plugged up,you will still get some heat.
If the control valve is stuck closed: NO HEAT.
Listen under the dashboard for a hissing sound.That may be the problem for the control valve not opening.(Turn the fan off)
I'll assume this is a late model truck.

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Most likely the blend door motor is defective.