04 Trailbazer engine swap...now defrost/vent/floor selector knob doesn't work.

[flash12]

Just swapped the engine out on my 2004 trailblazer, finished up late last night. Everything went pretty smooth. Only problem I have is now my selector knob to select between floor/vent/defrost/etc. doesn't seem to be working properly. Air will blow out the defroster, and out the floor but not the vents.

Of course I had the battery unhooked for about a week as we were working on this in the evenings, I assume they maybe need to be reset or something.
Anyone have any ideas. By the way this has the cheaper climate control with the manual sliders, not the fancy digital readout.

Thanks in advance.

[kayhanay]

check the vaccums from the engine to the dash. look at the vaccum diagram under the hood.

[maxwedge]

This truck uses solenoid actuators for mode door positions.

[flash12]

OK guys, the selector will select between defroster, floor, and floor/defroster but when you go to the next position which is floor/vent, or just vent it will not work. It appears it will select and work between all three positions that DO NOT include the vent.

I unhooked the battery while leaving the selector in various positions and then hooked it back up but still nothing.

Any thoughts?

Like I said before, when I parked the vehicle to swap out the motor it worked fine. It set with the battery unhooked for probably 2 weeks while we were getting and replacing the engine. Worked before but now doesn't. Not sure what would have changed.


Thanks!

[kayhanay]

Is it possible when you were replacing the engine, you may have hit the fire wall and knocked something loose on the other side of the fire wall.

[MT-2500]

Go threw the ac-heater relearn procedure.

[kayhanay]

I own a used car dealer and we disconnect the battery on all of our cars and i have 04 trailblazer and envoy and i never had any problems.

[flash12]

I have searched through the posts on the trailblazer and envoy forums and found some other people that had the same problem when they replaced the battery so I'm pretty sure it has something to do with that.

MT-2500 - What is the ac/heater relearn procedure? Is this something that has to be done with the Tech2 at the dealership?

Thanks guys for the responses!!

[MT-2500]

Not sure what it is on a 04.
The information can be found in a factory repair manual or a all data online sub.http://www.alldata.com/products/diy/index.html


Some older GM was remove the raido/RDO fuse.
Some newer GM you have to push certain buttons on the AC controls.
But when removing the battery cables always remove neg first and hook it up last.
You might try a proper battery disconnect and hook it back up neg last.
Good Luck