COUPLING AS 4991158 - Caterpillar

Illustration 1 g02477141
Connections of the Right Tail Lamps relay
This diagnostic code is associated with the Right Tail Lamps relay. The relay is controlled by the Relay Driver Module through an "ON/OFF" output driver. The FMI 06 diagnostic code means that the Relay Driver Module has detected an above normal current in the relay circuit. The diagnostic code is activated on the Machine ECM via CAN Datalink.The conditions that could cause this diagnostic code to activate are listed:
The relay has failed.
The energize circuit of the relay is shorted to a ground source.
The Relay Driver Module has failed. This condition is unlikely.Note: Before performing 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, that all connections are secure and that all connections are 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. Note: The following test procedure may cause other diagnostic codes to be activated. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE RELAY
Turn the key start switch and the disconnect switch to the ON position.
Observe the status of the active CID 3072 FMI 06 diagnostic code and disconnect the machine harness connector from the relay. Expected Result:When the relay is disconnected from the harness, the CID 3072 FMI 06 diagnostic code is no longer active. A CID 3072 FMI 05 is now active.Results:
YES - When the relay is disconnected from the harness, the CID 3072 FMI 06 diagnostic code is no longer active. A CID 3072 FMI 05 diagnostic code becomes active. The relay is the cause of the problem. Repair: Verify that the relay has failed by substituting a known good relay that is the same part number as the faulty relay. Replace the faulty relay.STOP
NO - The status of the active CID 3072 FMI 06 diagnostic code did not change when the relay was disconnected from the machine harness. The relay is not the cause of the problem. Proceed to Test Step 2.Test Step 2. CHECK THE ENERGIZE CIRCUIT OF THE RELAY FOR A SHORT The relay remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector J1 from the Relay Driver Module.
At the machine harness connector J1 for the Relay Driver Module, measure the resistance from contact J1-5 (wire 649-WH(White)) to frame ground. Measure the resistance from contact J1-5 (wire 649-WH(White)) to all of the other contacts that are used in the machine harness connector J1 for the Relay Driver Module. Expected Result: