Simple Power Mode Example

Power mode signal may be as simple as a battery voltage input wired to a particular ignition switch contact. If this is also battery voltage supply to module/device, module/device will only operate with ignition contact closed to battery voltage. For example, the starter relay when it is wired directly to CRANK/START ignition switch contact. When CRANK/START contacts are closed, starter relay is energized and provides a current source to starter and starter solenoid. When ignition switch leaves CRANK/START position, switch contacts open and starter relay is de-energized. This removes current source from starter and solenoid and starter operation stops. Modules using simple power mode are:

• Electronic Brake Control Module (EBCM).
• Engine Control Module (ECM).
• Inflatable Restraint Sensing and Diagnostic Module (SDM).
• Instrument Panel Cluster (IPC).