My 71 was born a 200 I6 was A/C. Somewhere in the process is swapping in the 302 the vacuum lines going through the firewall were cut and I’m guessing that’s why I don’t have any defrost control. There are 4 lines coming through the firewall, based on the pics below does anyone know which need to be connected and if full vacuum from the intake tree is appropriate? thanks, Bob
I have a 72 with the 200 I6 and A/C. One of those lines is a wire that would go to the A/C compressor clutch. Two lines ( brown and green ) would go to the vacuum controlled hot water valve - shuts off coolant flow through the heater core when A/C is called for. One line partially closes the valve and the other results in full closure. The other vacuum line would be the vacuum “ feed”which gets input from the vacuum canister. The canister gets its vacuum from a port on the intake manifold. Hope this helps.
Thanks guys, those help. I need to source a vacuum canister and hot water valve to get this fix sorted.
