Fuel Pump Electrical Circuit Diagnosis

Procedure
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.

Fuel Pump Connector:

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), and test operation.
6. Measure the resistance between the gray wire of the fuel pump connector and ground.

Fuel Pump Connector:

^ If the resistance is less than 5 ohms replace the fuel pump and filter sock assembly. Service and Repair
^ If the resistance is 5 ohms or greater repair gray wire for open in ground circuit, and test operation.