For the past few weeks my cruise control module has been buzzing. It only happens when the jeep is off. As soon as I start the jeep it stops. When it first started I could shake the jeep and it would stop for a few seconds then go back to buzzing. Also the light in the instrument panel that shows when the back hatch is open comes on when the cruise control module is buzzing. Both the light and the buzzing stop when the jeep is started and running. Any ideas what could be causing this to happen?