Vent door and/or actuator broken

[bigbacon]

I have a 2000 express 3500 LS and I think either the air diverter door is buster and/or one of the actuators is not working. Fan is fine.

It seems to be stuck in a leg/defrost mode. I don't hear any noises or anything when trying to change where the air should go. Can someone point me in the right direction to how I can diagnose what is the problem and where the parts are to actually test and replace as needed?

My googling of this lead me no where.

[MountainManJoe]

Welcome to the forum. Most of the time it’s a rotten vacuum source line running from the intake , over the engine and to the hvac system.

[bigbacon]

oh...I wonder that busted or forgotten when I had a bunch of work done not too long ago. God I hate to take it back and try to explain that. How difficult is it to get to that line or can I see it from under the dash just to see if it wasn't connected back?

[MountainManJoe]

It's pretty inexpensive to replace, but you may need to take the dog house off.

[bigbacon]

are there instructions somewhere on how to do this? the haynes repair manual is no help.

[MountainManJoe]

try charm.li but you don't need a manual.
It's very straightforward. You pull the old tube one out and stuff the new one in.