Fuel Pump Relay
- Disconnect negative battery cable. Remove Single-Board Engine Controller-II (SBEC-II) harness connector. Reconnect battery cable.
- Turn ignition on. Check for voltage at Dark Blue/Yellow wire on Cherokee and Comanche or Orange/Green wire on Wrangler in SBEC-II harness connector. If voltage is not present, go to step 5). If voltage is present, ground the wire. Fuel pump should work.
- If fuel pump does not work, check if relay clicks. If relay does not click, go to step 6). If relay clicks, ensure voltage is present at relay terminals No. 30 (battery) and 87 (fuel pump), and at fuel pump. See Fig 1
.
- If fuel pump still does not work, check ballast resistor (Cherokee and Comanche only) and fuel pump ground. If ballast resistor and ground are okay, replace fuel pump.
- If no voltage is present, ensure wire has continuity to fuel pump relay terminal No. 85. Ensure voltage (from ignition switch) is present at relay terminal No. 86. See Fig 1
.
- If all circuits are okay or fuel pump relay did not click in step 3), check resistance between relay terminals No. 86 and 85. See Fig 1
. Resistance should be 70-80 ohms. If resistance is not 70-80 ohms, replace relay.
- Disconnect negative battery terminal. Reconnect SBEC-II harness connector. Connect battery cable. Check if fuel pump works. If fuel pump does not work, see TESTS W/CODES
article in the ENGINE PERFORMANCE Section and check SBEC-II.
Courtesy of CHRYSLER MOTORS.