My truck heater only works on passanger side. Driver side is cold

SOURCE: A/C Heater problems

the main issue with this is either the thermostat or the climate control switch I do not know if your climate control switch is electronic or manual either way I would start out with the cheapest and go with the thermostat first good luck!

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

Check the actuator ot the pass side blend door for proper operaton. If it does operate remove it and confirm that the door is not broken.

SOURCE: Heater issue, driver side of 2004 Chevy Avalanche

1. Place the ignition switch in the off position.
2. Remove the HVAC/ECAS fuse for 10 seconds or more. It's in the under hood fuse box. Put the temp in full cold.
3. Install the fuse.
4. Start the engine. DO NOT TOUCH THE HVAC CONTROLS FOR LESS THAN 45 SECONDS.
5. Have any codes cleared with a scan tool.

Testimonial: "Thank you! Thank you! Thanks you! Worked perfectly, and its -32 here today!!!!!"

Colin Stickland

• 22516 Answers
• Posted on Jan 03, 2010

SOURCE: heater on driver side blows cold air

something wrong with flap operating device ?? would need to get my head under the dash to sort it though because their is so many variables of what could be causing it ,quick fix is to disconnect the operating mechanism and put a elastic band on it till the weather warms up

SOURCE: heater in 2004 avalanche blowing cold on driver side but hot on

Inside the heater box there are doors that are opened and closed by actuators on the outside of the box. Actuators are usually vacuum operated but sometimes can also be electric. They are often on top of the box and very difficult to get to. The problem is someone can tell you an actuator is bad, but you need to verify that by actually locating it and testing it. That, no one on the internet can do for you. Some dashboards need to be completely taken apart to get to some of the controls. (great engineering?)
If you don't have lots of experience working on these, though it is understandably expensive, I recommend you have a good shop do the work for you.
If you want to try it, get a haynes or chilton manual, read it first and then give it a try.