Fuel Pump Modulator

Fuel Pump Control:

PURPOSE
Provides a means for the ECM to control fuel pump circuit ground path.

OPERATION
The fuel pump modulator is similar to an ignitor or power transistor. It acts like a switch. The ECM triggers the switch at rapid intervals, completing a path to direct ground or through a resistor to ground. The higher the switching cycle (on time vs. off time) the more time the current path flows to ground. This supplies more voltage to the fuel pump, increasing discharge flow.