"Some time a go I was told that when I switched
the AC to REC to reuse the inside air that I would
get a vacuum on the that box on the firewall on the
passenger side. Will I dont. I have rebuilt the heater
control and fixed all leaks. Still no vacuum. Today
I played with it. Guess what? I get vacuum to it when
I slide to Vent. Then air comes out of the hole below
the dash on passenger side."
Arch, the pot that gets vacuum when you move the temp
control all the way to the left (Recirc) is under the
passengers hood but is contained within the heater
box. It can be seen through the opening in the front of
the heater box where the fresh air goes in.
The air coming out of the hole below the dash on the
passengers side I had always assumed to be "heater"
Although I get air from the hole below the dash when the
control is placed to "heater" I never investigated
to see if vacuum was present when the control was set
to "vent".
Mine may not be the best example (I just repaired a
bunch of PO modifications to the vacuum routing).
I will check for vacuum at that pot on "vent" after work
Monday.
Regards
Gary Zingle
1973 GMC 26 foot
the AC to REC to reuse the inside air that I would
get a vacuum on the that box on the firewall on the
passenger side. Will I dont. I have rebuilt the heater
control and fixed all leaks. Still no vacuum. Today
I played with it. Guess what? I get vacuum to it when
I slide to Vent. Then air comes out of the hole below
the dash on passenger side."
Arch, the pot that gets vacuum when you move the temp
control all the way to the left (Recirc) is under the
passengers hood but is contained within the heater
box. It can be seen through the opening in the front of
the heater box where the fresh air goes in.
The air coming out of the hole below the dash on the
passengers side I had always assumed to be "heater"
Although I get air from the hole below the dash when the
control is placed to "heater" I never investigated
to see if vacuum was present when the control was set
to "vent".
Mine may not be the best example (I just repaired a
bunch of PO modifications to the vacuum routing).
I will check for vacuum at that pot on "vent" after work
Monday.
Regards
Gary Zingle
1973 GMC 26 foot
