Fuel Pump Electrical Circuit Diagnosis

NOTE: This test assumes that the Auto Shut Down (ASD) relay is functioning properly. Before proceeding with this procedure verify ASD relay operation.
1. Raise the vehicle on a hoist.
2. Remove electrical connector at fuel pump.
3. Inspect the connector for corroded, damaged or spread terminals. Clean, repair or replace the connector as needed.
4. Measure the voltage between the dark green/black wire of the fuel pump connector and ground.
^ If voltage is over 10V go to step 6.
^ If voltage is less than 10V repair wiring between ASD relay terminal 87 and the fuel pump connector, (dark green/black wire).
6. Measure the resistance between the gray wire of the fuel pump connector and ground.
^ If the resistance is less than 5 ohms replace the fuel pump and filter sock assembly.
^ If the resistance is 5 ohms or greater repair open in ground circuit.