Normal Operation
WARNING: This page is about a different car, the 2003 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
The electronic parking brake (EPB) switch circuits 8-CG15 (WH/BU) and 10-CG15 (GY/VT) receive a reference voltage from the EPB module when the switch is in its neutral position. This voltage is between 3.5 and 4.5 volts. When the switch contacts close on the apply or release side, a resistor inside the switch is shorted, causing a voltage on switch circuits 8-CG15 (WH/BU) or 10-CG15 (GY/VT) to change from 1.5-3.0 volts. When the EPB module receives this voltage range on the apply or release circuit, an output signal is generated to the actuator to apply or release the EPB.