if the fan motor isn't working, the fan motor has likely got a loose connection of some sort. if the fan does work but the reguler vents don't you might have something blocking them.
If the air vents of the Chevy trailblazer 2004 are not blowing air, have the fuel pump checked.
The air of your Chevy trailblazer 2004 blow out of the front vents when the air conditioner is on because the air condition is faulty and it needs repair.
The mode door actuator has failed. We have instructions for repair at www.trailvoy.com
If your 03 Trailblazer blows heat out of the back vents when set on AC sometimes, it could be because of a faulty blower motor resistor block.
Check for a vacuum leak -sounds like it is starving for vacuum and reverts to the default position
what could be wrong is you might have a vacuum leak somewhere or something is disconected in the dash that switches to the vents. I had a problem with my 97 blowing air threw the floor and it was a little vacuum leak that caused it
Control problem, blend door not working are the places to start
Could be the mode door actuator. For more info visit our enthusiasts forum at www.trailvoy.com
When there is a problem with the vent system it dfaults to the defrost setting. Sounds like you have a problem in the doors that direct the air flow.
i had the same problem .. i got frion and put it in and it worked fine
Probably the mode door actuator. We have instructions on the replacement procedure on our enthusiasts forum at www.trailvoy.com
If the climate control on a 2003 Trailblazer will not switch from feet to head vents, try changing it to defroster then back to head. The mode button on the dual climate control model can only be switched from face/feet to feet and then to defrost. The feet and head vents worked at the same time.