Glad I found this board. I've been doing some research here and now have some specific questions about this Blazer. 4WD w/air 4.3l. I have read here that the vent system defaults to the floor when no vacuum is present at the switch. I have both the floor and defrost vents blowing. Does the fan blow faster when the switch is set to High AC? It has been so long since I have had air working that I can't remember what it does. I'm guessing from what I have read so far with both the floor and defrost vents blowing air I prolly nead s new switch. Just to cover all my bases can someone tell me where the vacuum lines go through the firewall? I'm trying to get this done between thunderstorms and everytime I barely get the hood up and started good before another squall is upn me. I'm not used to the way GM/Chevy does things and often I am unsure what and where to look at. Thanks in advance.

 

im not sure where they come threw the firewall but i do know that when i put mine in max ac it does blow faster.. when i got my blazer the dumb guy didn't have my lines hooked up he had a screw in on of the lines to block the air.. idk why someone would do that but anyways.. if you need me to look on my blazer for where the vacuum lines come out i can tomorrow after work.

 

Thanks. I appreciate it. Does anyone have the full diagram as it relates to the Vac/ac system handy?

 

Anyone? Hello?

 

I have never found a good diagram in any of the references that I have for the complete vacuum hose system. There are, however, several other threads where I have posted the under dash vacuum hose schematic.

I believe that there was only the manual HVAC offered in 96.

Here is a diagram for the manual HVAC system in a 97 which should be the same as yours:

 

Thank you very much. Now I should be able to get this thing fixed.