Vaccum leak????HELP!!

Recently my cruise control and heater duct control went out on me, and after researching this online I led to the conclusion that is is caused from a vacuum leak. So I went to the Chevy dealer and they printed me out a vacuum diagram for my 1994 Corsica, and told me to look for the vacuum reserve canister, which should be on the drivers side, a round shaped object....I CANNOT fine this anywhere!! Can someone advice, please!!! Tia Lindsey