LS-Coupe A/C defaults to DEFROST

[dville_gt]

So every time I turn the ignition on with the a/c on it defaults to the defroster. I understand that this is because there is no vacuum and it goes to defrost with no vacuum. So obviously the Mustang came with a check valve or something to keep vacuum in A/C vacuum lines. Anyone got a part number or link to where I can grab one of these?

[Baron Von Crowder]

I have one at the shop, if you need it.

[Beenfetchedlately]

There's a vacuum line inside the harness that would plug into a vacuum source under the map on the intake on an LS1. Did you reconnect that to any of the Ac equipment? It also works
Similar in the GM cars.

[dville_gt]

I have one at the shop, if you need it.

Ya, I need it!

There's a vacuum line inside the harness that would plug into a vacuum source under the map on the intake on an LS1. Did you reconnect that to any of the Ac equipment? It also works
Similar in the GM cars.

Ya, I have the vacuum source connected from the A/C controls to the intake manifold. Works fine when the engine is running, but when the engine is not running (thus no vacuum) it defaults to the defrost vents.