[Pits4sprint]

I have a 96 Blazer 4wd that sat for a year while I rebuilt the engine. After getting it all back together and running great I found out that the AC/Heater selector switch isn’t working. It stays on defrost all the time. After checking all fuses, I pulled the switch and found that it is a vacuum switch with color coded lines. When separated (engine running) there isn’t any vacuum at any port, but when vacuum is applied to a port the airflow is redirected to vents (only had enough lung power to try 1 port). I heard that there is a vacuum pump which supplies the vacuum, but I can’t find it without pulling the whole dash. My Chilton’s isn’t any help at all. Thanks Rob