Hook up a Tee with a vacuum gauge going to your reserve canister if you can. Try using one side of your repair splice if that's in a convenient location. Switch on and let the engine generate your vacuum until you reach 18 inches at the canister. Switch off and read your residual vacuum or better still, the rate at which you're loosing vacuum. If vacuum holds, that door should open. Either your can or the check valve and lines going to it are loosing vacuum or your switch is reversed ie open is closed and closed is open. Yes, that can happen........you did say it was a repro switch.