So, it's getting pretty hot here in my part of the world, and I'd like to charge up the A/C system. But I need to sort out why the system won't direct the air to the main vents. I am only getting air out of the defrost vents, currently.
The flaps were recovered several years back. And the system holds a vacuum when I apply a vacuum at the line on the rear of the intake manifold. Vacuum unit "C" on the picture below was repaired when I had it all apart before, but it might be bad again. However, when I look at the diagram, I think my issue is with vacuum unit "B" (the only one that controls air to the instrument panel vents).
Before I start to rip the dash out, I'd like to do some less intrusive troubleshooting. Is the vacuum distribution thingy (circled in red) easily accessible? I'm wondering if I can get to it by removing the knee bolster?