Heater vac pressure

[mriz]

Today I replaced the heater core and vac lines as they were not even close to the diagram from what the PO. had done. Problem is I can only hold vacuum pressure with the S line from the heater control manifold connected directly to the vac source on the engine. All functions work properly an dholds cav pressure . Once I connect the Ac solinoids the system no longer pulls vac pressure .The bottle does hold pressure on it's own so I am at a loss as to why no pressure. It's a 1977 with factory AC if anyone can help .Thanks

[TomoHawk]

Can you find the dashpot for the fresh-air door?

thx

[mriz]

Yes, that operates as it should. It's just when I connect the vaccum lines to the solinoids I hav eno vac pressure.