BATTERY CHARGER 6L4027 - Caterpillar

Illustration 1 g03480140
Fuse Panel film depicting the relay locations.
(1) Backup Alarm Relay
(2) Secondary Steering Relay
Illustration 2 g03872239
Transmission/Chassis ECM J2 Relay connections
The preceding diagram is a simplified schematic of the relays and the relay connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the electrical schematic to view the entire circuitry of the machine.Troubleshooting Procedure
Prior to beginning this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Table 2
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With Relay Circuit
Code present. FMI 3 diagnostic code, proceed to Test Step 2.
FMI 5 diagnostic code, proceed to Test Step 3.
FMI 6 diagnostic code, proceed to Test Step 6.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Machine Harness For A Short
A. Turn key start switch and disconnect switch OFF.
B. Disconnect harness connection at relay.
C. If relay connected to ECM, disconnect J1 and J2 connectors from ECM. If relay connected to Switch Panel, disconnect all switch panel connectors.
D. Measure resistance of relay signal contact to all J1 and J2 connectors, if relay is wired directly to Transmission/Chassis ECM. If relay is wired directly to switch panel, measure resistance of relay contact to all switch panel connectors.
Each reading greater than 5K Ω. OK: All resistance measurements are greater than 5K Ω.
Proceed to Test Step 8.
NOT OK - One or more readings are less than 5 Ω.
Repair: A short exists between the signal contact and the circuit with the low resistance. Repair or replace the machine harness.
Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit.
STOP
Begin Process For FMI 5 Troubleshooting HERE
3. Check The Harness For An Open.
A. Key start switch and disconnect switch OFF.
B. Disconnect the relay from the wiring harness so there is no longer a coil. Install a jumper wire from the signal to return contacts in place of the relay.
C. Disconnect J1 and J2 connectors from the ECM.
D. Review the electrical schematic (above) to identify the signal and return wires for the relay.
E. Use a multimeter to measure the resistance From the signal to return wire on the ECM harness.
The resistance of the coil is less than 5 Ω. OK: The resistance is less than 5 Ω.
Proceed to Test Step 4.
NOT OK - The resistance is greater than 5K Ω. The harness has an open.
Repair: Replace or repair the harness.
Note: After the harness is replaced, confirm the diagnostic code is no longer active.
Note: A resistance greater than 5 Ω but less than 5K Ω