No hot Air on Driver side vent. 2004 W/Truck with

check for a faulty climate control module.

If it has dual zone temp. control it is most likely the heater control panel.

needs gas topping up end of story .

if it has dual zone climate setting it could be stuck in the cool setting. if it is not blowing any air it could be the duct came loose and it is blowing the air inside the dashboard. it will require you to pull the dash apart to inspect what the exact cause is. it could be anything from a bad temp setting switch in the climate control panel to a bad vac line that that switches the air from hot to cold. any other info you could give me may help such as if it is full electronic climate or manual knobs, dual zone, is it blowing any air or just no hot air.

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

There are two possabilitys for this issue. First is a low A/C charge will cause this. Second the dual zone A/C has temp actuators for each side. It is possible one has gone out or is stuck.You can try pulling the fuse for the HVAC for a minute or two, this will reset the system and it will relearn the door positions. 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

check the coolant level on the radiator..it sounds like its low

U will need to replace the pass side air temp control blend door acuator motor.

On a w body car with a single temp adjustment control (not a dual zone) your problem should be a low refrigerant charge. Due to the design of this evaporator, a low refrigerant charge will cause the furthest areas from the inlet and outlet hoses (the drivers side) to not remove the heat from the incoming air. This allows the air on the drivers side to be outside temp but refrigerated on the passenger side. In cars with Dual Zone controls you must not only verify the refrigerant charge level, but also check the mode doors which control the air flow and regulate the temp. To check the refrigerant level do not use pressure gauges alone. Verify a proper charge level by checking the temperature of the two aluminum lines going in to the firewall of the vehicle. With the A/C set to high the temperatures should be within 5 degrees of each other. If not, then there is a charge issue. I hope this helps