ac controls

[Rick Bollinger]

I have been going through my A/C & heating system. New cables, replaced broken arm and bad fan switch, vacuum lines and cleaned system. This is a new to me truck and don't believe this system has worked in years. The vacuum comes on when the top lever is moved to the left. This opens up the inside passenger vent and closes the outside air. It also turns on the heater valve. But I cannot get the defrosters on with the vacuum on. I am thinking the vacuum is working backwards. It is a 2 port vacuum switch. I could use some help.
Thanks
Rick