Fuel Pump Relay

Cherokee and Comanche models have a fuel pump relay located in the power distribution center, next to coolant recovery bottle. On Wrangler, the fuel pump relay is located in power distribution center next to battery.

The feed side of the relay coil is powered by the ignition switch. The relay is energized by the engine controller by grounding the other side of the relay coil. The relay contacts are normally open and will close when the engine controller provides a ground path for the relay coil.

The fuel pump circuit is completed during cranking and whenever the engine is running. If the ignition key is turned to the RUN position, the fuel pump will operate for 1-3 seconds and then shut off. If the engine controller DOES NOT receive a crank or run signal, it deactivates the fuel pump by opening the relay coil ground circuit. The 1-3 second time limit is used to prevent unnecessary operation of the fuel pump once the system is pressurized. If the engine were running, the engine controller would maintain the fuel pump relay coil ground allowing continuous operation of the fuel pump.