Diesel (Dual Tank)
NOTE:
On primary fuel tank, resistance between terminals "A" and "B" at fuel gauge sender (component side) should be zero ohms when tank is empty and 90 ohms when tank is full. On secondary fuel tank, resistance between terminals "A" and "D" at fuel gauge sender (component side) should be zero ohms when tank is empty and 90 ohms when tank is full.
- Turn ignition off. Disconnect fuel pump balance module harness connector. Turn ignition on. If fuel gauge indicates full, go to step 5. If fuel gauge does not indicate full, go to next step.
- Turn ignition off. Disconnect instrument cluster harness connector. Check continuity between ground and terminal No. 16 at instrument cluster harness connector. See Figure. If continuity exists, go to step 4. If continuity does not exist, go to next step.
- Replace instrument cluster.
- Repair short to ground in Purple wire between fuel pump balance module and instrument cluster.
- Disconnect both fuel gauge sender harness connectors. Check continuity between ground and terminals "B" (Light Blue wire) and "C" (Dark Blue/White wire) at fuel pump balance module harness connector. See Fig 1. If continuity exists in either check, go to next step. If continuity does not exist in both checks, go to step 7.
- Repair short to ground in appropriate wire.
- On secondary fuel tank, measure resistance between terminals "A" and "D" at fuel gauge sender (component side). On primary fuel tank, measure resistance between terminals "A" and "B" at fuel gauge sender (component side). Resistance should be zero ohms when tank is empty and 90 ohms when tank is full. If resistance is as specified, go to next step. If resistance is not as specified, go to step 11.
- Check continuity between ground and terminal "A" (Black/White wire) at each fuel gauge sender harness connectors. If continuity exists in both checks, go to next step. If continuity does not exist in either check, go to step 10.
- Replace fuel pump balance module.
- Repair open in appropriate Black/White wire between appropriate fuel gauge sender and ground.
- Replace appropriate fuel gauge sender.