This is on my 2008 express 3500 with a 6.0 motor

Want to replace all the vacuum lines anyway, they all seem brittle

But right now if you get on a the gas for a hill etc the vents stop blowing out the middle and go to defrost
so i got the little vacuum control valve? The $6 one and was going to replace it to start

there are 2 plastic type lines that run through the firewall under the dash, the other side of those 2 in the engine compartment both broke off, they have rubber fitting onto both of them, one goes to the small vacuum thing and the other to that bigger round valve with the green arrow
does anyone have a parts diagram or the name of the 2 wire bundle that goes through the dash there?

thank you

 

Here are the pics

 

Think i found it, hope it is not discontinued, will contact dealer in the morning

does anyone have suggestions on any other vacuum stuff to replace? I am doing all the lines there in that area and hopefully this air valve actuator harness

would like to replace any vacuum stuff in the engine compartment that can get old and crack like this

thanks

 

See here. https://chevroletforum.com/forum/exp...-issue-117027/

 

Some great info in that thread, thank you