Principles of Operation
WARNING: This page is about a different car, the 2004 Lincoln Aviator. However, it is still accessible from the selected car via links, so may be relevant.
The brake pedal position (BPP) switch is normally closed to ground. When the brake pedal is applied with the speed control system engaged, the BPP switch closes (to battery voltage), putting the speed control in stand-by mode.
NOTE:
A redundant brake deactivator, the brake pressure applied switch (BPA) switch, is provided as an additional safety feature.
NOTE:
The speed control module is integral to the powertrain control module (PCM).
The clockspring provides the electrical interface between the steering column wiring and the speed control switches in the steering wheel.
The inputs to the powertrain control module (PCM) for the speed control system are the:
- Anti-lock brake (ABS) module
- Digital transmission range (TR) sensor
- Speed control deactivator switch
- Speed control switches
- Vehicle speed signal (VSS)
The input to the speed control actuator comes from the powertrain control module (PCM).
The output of the speed control actuator is through the speed control cable. The speed control cable then positions the throttle as requested.