Dual thermostat contol not working on passegner side. blows only hot air.

There may be a fault in your Totally Integrated Power Module. Are the signals coming on and just staying steady? Are yourvparkkng lights working? Hazard warning? If so, I'd start looking at a defective turn signal switch.

check for a faulty climate control module.

Its called "AC Vent Door Actuator" when this fail they will stay open or Closed, this will happen on vehicles that have Dual Climate control. You can Google it just type Year, make ,model and AC vent door actuator after that. It will definetly have to be replaced. Good Luck.

My 02 Century has dual temp controls . One for driver for passenger. Make sure you don't have the dual climate enabled and just set for heat on your side and AC on the passengers

You will need to replace the drivers side temp actuator. It is available at your local dealership.

I had the same problem but it was blowing hot air on the passenger side of the car. I assume you have the dual zone controls that I have as well. The problem is most likely the damper that controls the flow of hot and cold air into the car. The motorized component of the damper is most likely not working and its stuck in the hot air position.

I had mine replaced by a repair shop so I cant tell you how to replace it but it may be something that you can do if you have the time and patience to work on it.

Good luck

You have dual zones that are controlled by temperature actuators the passenger side has lost its memory or has gone bad you can put it in self programming by disconnecting the battery for ten minutes then hook it back up start the truck turn the temperature control on but do not touch any other controls let it go thru the self programming for about 6 to 7 minutes then select your temperature you want if it still does not work properly you may have a bad actuator or a bad connection at the actuator

The thermostat adjustment control may need to be replaced. Also check the hose on the back for cracks, clogs, or missing.

The lever contols behind the dash have probely dislodged themselvies this can be very hard to fix.

Is it leaking antefreeze?
The thermostat might be gone or needs a bigger thermostat
It could be a vaccum leak for the drivers side blowing cool air and the passenger side blowing warm air
Does it have dual air control switches one for drivers side and one for passengers side?