Just this morning, after the ignition switch reached full on, a banging began behind the glove box. Each time it bangs about 20-25 times then stops. My guess it's an electric air delivery motor with a broken tooth/cog, etc. Anyone experience the same event and what would it take to repair it? Hopefully the dash doesn't have to be removed.

Thanks!

 

Most likely suspect is the air door actuator.

Seen here

 

Here's another diagram, view from near the left front wheel. You're looking at #38(behind the glove box)
GM P/N 15842338 ACTUATOR,AIR INL VLV(ACDelco #15-73513)

 

#38 would be on the drivers side, #10 is up on the passengers side in the left of the glovebox

 

Thanks for the quick reply with diagrams! Pulling the g-box should gain me access?

 

Are you sure? It doesn't seem like the inlet would be over on the driver side. #10 is listed as ACTUATOR,TEMP VLV(ACDelco #15-73108) GM P/N 10393075

https://www.wholesalegmpartsonline.c...g=conditioning

#34 is the filter, and it shows over on the left side of the diagram also.

 

If it quacks like a duck on that side it could be listen with the glovebox door open.

 

And the heater core lines run into the engine bay. Just trying to make sure we're looking at this diagram right.

 

RJ. Your diagram is if you're looking at it from the engine compartment side.
(note the cabin filter, blower motor, etc. locations )

 

That's what I think also, FMG. I wrapped my head around this a year or so ago. Just trying to remember what wrapping paper I used...