ROD,PUSH 1039583 - Caterpillar

Machine ECM
The following is a list of Diagnostic Trouble Codes (DTC) associated with the electrical relays for the Machine ECM. Some of the relays on the machine are electrically connected to the "Switch Panel" module the majority are located inside the fuse panel. The Machine ECM receives information and sends control signals to the "Switch Panel" via the CAN Data Link.
Table 1
Machine ECM (MID 299)
DTC Code Description System Response
781-3 Lighting Relay : Voltage Above Normal Related lighting system will be ON continuously.
781-6 Lighting Relay : Current Above Normal Related lighting system will be ON continuously.
2912-3 Front Wiper Speed Control Relay : Voltage Above Normal Wiper system will not function.
2912-6 Front Wiper Speed Control Relay : Current Above Normal Wiper system will not function.
3634-3 Boom Light Relay : Voltage Above Normal Related lighting system will be ON continuously.
3634-6 Boom Light Relay : Current Above Normal Related lighting system will be ON continuously. Possible Causes for an FMI 3 Diagnostic code are:
The ground wire is open.
The signal wire is permanently open.
The signal wire is permanently closed.
The relay has failed.
The Machine ECM has failed. This situation is unlikely.Possible Causes for an FMI 6 Diagnostic code are:
A short to ground exists.
The relay has failed.
The Machine ECM has failed. This situation is unlikely.
Illustration 1 g03727759
Schematic of the relay circuits associated with the "Switch Panel"
Note: The diagram above is a simplified schematic of the "Switch Panel" connections. The schematic is electrically correct, however, not all of the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, UENR5374 for the complete schematic for sales models 312F and 313F. For sales models 316F and 318F refer to Electrical Schematic, UENR5345.Diagnostic Trouble Code Procedure
Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this 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. Check the wiring harness for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure.
Table 2
Troubleshooting Test Steps Values Results
1. Identify The Active FMI Code Associated With Relay Circuit
Code present. FMI 3 diagnostic code, proceed to Test Step 2.
FMI 6 diagnostic code, proceed to Test Step 3.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Machine Harness For A Short
A. Turn the key start switch and disconnect switch to the OFF position.
B. Disconnect the harness connection at the relay.
C. If relay is connected to the ECM, disconnect the connector from the ECM. If relay connected to the "Switch Panel", disconnect all "Switch Panel" connectors.
D. Measure resistance of relay signal contact to all Machine ECM connections. (If the relay is wired directly to "Switch Panel", measure resistance of relay contact to all "Switch Panel" connectors.)
Each reading is greater than 5K Ω. OK - All resistance measurements are greater than 5K