I have a 2016 express for my work van. The AC has stopped blowing out of the cabin facing events and will only blow from the defrost vents. I have had it in the shop and it worked great for a day and it s now doing the same thing. Is there a way to apply suction or blow air into and clamp the line on one of the vacuum lines in the passenger foot well to get the vent control to switch to cabin temporarily until I can get it back into the shop?

the fix last time was replacing the line from the vacuum ball under the battery all the way into the cabin last week.

Thanks for any help that can be offered.

 

In addition to the use of vacuum, looking at the 2013 system description for an Express van seems to say that there is a mode related actuator or vacuum valve that is electrically controlled. If your 2016 has that, it sounds like maybe that could be bad.

This description is for the operation of the 2013 Express HVAC system, but may be similar. Look under the heading "air distribution":

https://charm.li/Chevrolet/2013/Expr...487/#qrcontent

 

I joined this forum so I could tell you what my fix was for this issue. I had to remove the dog box today to replace my evap solenoid. While it was off, I decided to also track down what is wrong with my HVAC controls. Like you, I only had air blowing from the defrost and floor, the default location. I changed the vacuum line that runs from the reservoir to the check valve. Then while my dog box was removed, I changed the line from the intake to the check valve and also the check valve. It was cheap. I still had no air blowing through the vents. I did however hear a hissing noise behind the control panel. Turn the zone selector to AC and turn the fan all the way down. If you hear hissing behind the control panel, you have the same problem as me, and I know the fix. If you have hissing in the passenger footwell, check those connections.

If you hear hissing behind the control panel, the multi-color lines may not be making a seal. Go buy silicone lube in the plumbing section of your hardware store. Apply a thin coat and plug it back up.