COVER ASSEM. 3N7937 - Caterpillar

Table 5
Begin Process For FMI 3 Troubleshooting HERE
Troubleshooting Test Steps Values Results
2. Check the Harness For an Open
A. Turn key switch and disconnect switch OFF.
B. Disconnect the switch from the machine harness.
C. Disconnect the J1 and J2 machine harness connector.
D. At the machine harness connector for the switch, place a jumper wire between the signal contact and frame ground.
E. At the machine harness connector for the ECM, measure the resistance between the signal contact and frame ground.
The resistance is less than 5 Ω. OK -The resistance is less than 5 Ω. The circuit is correct.
Proceed to Test Step 3.
NOT OK - The resistance is greater than 5 K Ω. The circuit is open.
Repair: Repair or replace the machine harness.
Note: A resistance that is greater than 5 Ω but less than 5 K Ω indicates a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5 K Ω indicates an open in the circuit.
Proceed to Test Step 10.
3. Check the Harness for a Short
A. The keyswitch remains OFF.
B. All harness connectors remain disconnected.
C. Remove the jumper wire installed in the previous step.
D. At the machine harness connector for the ECM, measure resistance between the signal contact and all other contacts in the J1 and J2 harness.
The resistances are greater than 5 K Ω. OK - The resistance is greater than 5 K Ω. The harness circuit is correct.
Proceed to Test Step 4.
NOT OK- The resistance less than 5 Ω.
Repair: A short exists in the harness between the signal circuit and the wire with the low-resistance reading. Repair or replace the machine harness.
Note: A resistance that is greater than 5 Ω but less than 5 K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5 K Ω would indicate an open in the circuit.
Proceed to Test Step 10.
4. Check the Ground Source for the Switch.
A. The keyswitch remains OFF.
B. All harness connectors remain disconnected.
C. At the switch, measure resistance between the ground contact and frame ground.
The resistance is less than 5 Ω. OK - The resistance is less than 5 Ω.
Proceed to Test Step 5.
NOT OK - The resistance is greater than 5 K Ω.
Repair: The switch does not have a good ground source. Replace the harness between the switch and the ground source.
Note: A resistance that is greater than 5 Ω but less than 5 K Ω indicates a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5 K Ω indicates an open in the circuit.
Proceed to Test Step 10.
5. Check the Operation of the ECM.
A. The keyswitch remains OFF.
A. Reconnect all harness connections.
C. Using a wire removal tool, remove the signal wire and socket from the machine harness connector to the ECM.
D. Turn the keyswitch ON.
E. Use a multimeter probe to contact the ECM pin through the empty space in the harness connector.
F. Ground the other end of the multimeter probe