okay does anyone have the answer to this i replaced the vacuum relays and rebuilt the vacuum canisters on my 74 vette the lights would go up and down on que for about the first few minutes the car was running then all of a sudden they wouldnt shut even when the car was off. they are not releasing vacuum even if i pull the manual switch under the dash could this be the headlight switch gone bad or something i did wrong i also replaced the check valve after this happened with no help if i pull the vacuum line from the relay or the canister i can manually push down the lights but not until then ?? any help would be appreciated.