SHIM 2750511 - Caterpillar

Possible Causes and Schematics
Possible Causes for an FMI 3 Diagnostic code are:
The return circuit is open.
The signal circuit is open or the alarm is disconnected.
The signal circuit is shorted to the +battery.
The alarm has failed.
The monitor has failed. This condition is unlikely.Possible Causes for an FMI 5 Diagnostic code are:
The alarm has failed.
The signal circuit for the alarm is shorted to ground.
The monitor has failed. A failure of the monitor is unlikely.Possible Causes for an FMI 6 Diagnostic code are:
The energize circuit of the backup alarm is shorted to ground.
The backup alarm has failed.
The ECM has failed. This condition is unlikely.
Illustration 1 g06271224
Schematic of Backup Alarm
Note: The diagram above is a simplified schematic of the connections for the backup alarm. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic for the complete schematic.Troubleshooting Procedure
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, 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 The Active DTC Code Associated With The Suspect Circuit
Code present. FMI 3 diagnostic code. Proceed to Test Step 2.
FMI 5 diagnostic code. Proceed to Test Step 5.
FMI 6 diagnostic code. Proceed to Test Step 8.
Begin Process For FMI- 3 Troubleshooting HERE
2. Check The Alarm
A. Turn the key start switch and the disconnect switch to the OFF position.
B. Disconnect the alarm from the harness.
C. Use jumpers to connect the respective terminals of the alarm to +battery and ground.
D. Turn the key start switch and the disconnect switch to the ON position.
The alarm sounds OK - The alarm sounds.
Proceed to Test Step 3.
NOT OK - The alarm does not sound.
Repair: Replace the alarm.
STOP
3. Check For An Open In The Alarm Circuit
A. The key start switch and disconnect switch remain in the OFF position.
B. The harness connector remains disconnected from the alarm.
C. Disconnect the J1 and J2 connectors from the monitor.
D. At the harness connector for the alarm, install a jumper wire.
E. At the harness connector for the monitor measure the resistance at the contacts for the alarm.
The