Fresh air vent operation

[sleepchamber]

I have a 1985 C10 and have recently cleaned out the cowl area as well as the area where the fresh air vent door is on the passenger side footwell.  The vent door and vacuum hose and hardware all appear to be in great shape but i cannot figure out at what setting on the air/heat control panel that causes the vent door open?  Just want to know if it is working correctly.

[zieg85]

Vent/cold should open it.  Make sure you have vacuum to it.  If you don't the line going to it may be dry rotted or the control itself is bad.  I assume you do have vacuum coming into the controller so everything else works???

[sleepchamber]

yes....air and heat as well as all vents are in working order.  i will check to ensure there is vacuum on this end.  thanks for the reply.