Range Rover
WARNING: This page is about a different car, the 2000 Land Rover Range Rover, 2000 Land Rover Discovery, 1999 Land Rover Range Rover, and 1999 Land Rover Discovery. However, it is still accessible from the selected car via links, so may be relevant.
After the Body Electrical Control Module (BECM) receives a road speed signal from ABS ECU, it then sends that signal on to cruise control ECU. Cruise control ECU compares road speed signal with requested cruise speed, and adjusts output to vacuum pump as necessary. Cruise control will only operate between 25-125 MPH. Cruise control will not operate if there is no vehicle speed signal.