There should be 3 vacuum hoses coming through the engine compartment to the fire wall.

2 of them are connected together, side by side, with colored stripes on them (white and green). This set goes to the headlight cover canister/motor and through the firewall to the headlight switch.

3rd one goes from the reservoir canister under the fender to the "tee" near the fire wall.

At the "tee", 1 hose goes through the firewall to collect "clean" air for the system. The other hose goes to one of the branches on the vacuum "tree" on the firewall to provide vacum to the headlight system.

Hopefully, this will make sense to you and allow you to get those COOL headlight covers working again.