Hello and good morning. Generally the charcoal canister is hooked to the throttle body via a canister purge solenoid. This is a computer controlled solenoid and does not allow charcoal vapors to move to the intake until the computer commands them to. Check with the manufacturer of the wiring harness and ask them if it has provisions for a canister purge solenoid. If it does, then it's easy, run those wires to a canister purge solenoid and place that solenoid in between with the vacuum line to the throttle body. With that in place, you can tie that line into manifold vacuum because it will not flow until the computer opens the solenoid.
Your JA Expert,
I believe you should connect the vacuum control to a ported vacuum source. Try that and see how things seem to work.
Thank you very much. Let me know if you need any additional help as you proceed. Your finished product should be awesome.