I unhooked the vacuume connector to the switch and traced the hoses. four of them go to two silver canisters under the dash another one goes into the dash and I lost it. I assume that one of these hoses has to go to the engine to provide the vacuume to the switch. I don't hear any air/ vacuume from the hoses at the connector with the engine running. How can I find out where the vacuume hose from the engine is located? Is there a diagram available to trace the hoses?