The "control module" under the battery tray is in fact a vacuum pump. The hose from the black nipple terminates under the dash at the actuator attached to the gas pedal, and is tee'd in to a valve at the brake pedal. There is no vacuum at either the hose or the black nipple unless the vacuum pump is running. In other words, no conection to engine vacuum. When you activate the cruise, the electronic control unit activates the vacuum pump, which creates vacuum and pulls the actuator at the gas pedal. The most common failure is a broken/corroded hose between the pump and actuator. You will probably have to remove the battery and tray to access the hose. The break is usually where the hose runs along the fender under the battery tray. Simply cut out the damaged hose and splice with some rubber vacuum hose