Checking Vacuum Motor

Check all hoses for damage. With engine off, observe position of damper door through snorkel. Damper door should be in such a position that heat stove passage is covered. Apply at least 9" of vacuum to diaphragm assembly through hose disconnected at sensor unit Damper door should completely close snorkel passage when vacuum is applied. With vacuum applied, clamp hose to trap vacuum in diaphragm assembly. Snorkel passage should remain closed, if not there is a leak in diaphragm assembly.