1970 Air Grabber

Hope someone can give me some advise about my air grabber that just stopped working. It looks like the vacuum hoses are okay and all my operating parts are relatively new. Appreciate all the advise and clues I can get....thanks all.

Way back when I had one, I put a couple small drops of transmission oil into the dash switch hose nipples, that cured a pesky leaky switch.. I think the rubber inside the switch wasn't sealing and wasn't holding vacuum in the system. Other than that, some will surely suggest checking the diaphram actuator if the internal baffle is leaking.

EZ to test...
Disconnect the cannister and try running a vacuum hose directly to the air-flap diaphram from the supply nipple on the intake manifold. This will bypass the switch and longer hoses..
Check it for opening and closing..

Just my $0.02..