2003 Chevy Trailblazer no air from main dash outlets

Automatic HVAC system or manual
if automatic try this

Clear all DTCs
Place the ignition switch to the OFF position.
Disconnect the scan tool.if any
Remove the HVAC B fuse for a minimum of 10 seconds.
Re-install the HVAC B fuse.
Start the vehicle.
Wait 40 seconds for the HVAC control module to re-calibrate.
Verify that no DTCs have set as current DTCs.



manual
check for vacuum leak and check vacuum source

Unit has automatic HVAC, tried the reset procedure nothing changed, any other ideas?

Next step know should be to determine if BCM ,HVAC control module ,or PCM have set any codes that may effect HVAC operation

No codes of any kind, suspect the HVAC control unit just not giving the command to open the vent

Are you able to communicate with the BCM or HVAC module ?
was all fuses checked
in some rear cases you may need to take it to the dealer have it reprogrammed

I am being told that it needs to be replaced, $$$$$$

Sorry so it was checked and was unable to reprogram

they are big money

So I understand, real big money close to $500.
The reprogram that you talk about is that flashing the module with another computer, or removal of the power and allowing the module to return to factory values ?

Yes it is big $$$
very rear case when removing the power it may work never did for me
have to plug in another computer (dealer )and download program that makes it work
its almost like a driver for the computer
let me know what the out come fix please

good luck

The fix was replacement of the control module, ( Model 15195331 ), and a actuator, I was told that this particular year 2003 the module could not be reprogramed, i have no way of knowing for sure. Does that make sense to you.
Thanks Gary

Good all fixed
I know if can not reprogram it have to replace it
some of the early years were like that
so I do not see it strange thing that they had to replace it
happy driving
thank you