SUPPORT AS 2363098 - Caterpillar

short circuit is a failure in the isolation of an electrical circuit that results in the flow of electrical current through an unintended path. Short circuits can be caused by:
Damaged wire insulation
A damaged or contaminated machine harness connector
A failed componentA circuit can be shorted to:
Frame ground
A ground circuit
A battery circuit
A power supply
A signal circuitShort Circuit to a Ground Source - Will cause excessive current to flow through the circuit. Excess current will cause voltage in the circuit to decrease. In a circuit such as a lighting circuit, excess current will cause the fuse or the circuit breaker to open. In a circuit that is controlled by an ECM, the ECM will detect a change in the voltage. The ECM will activate a diagnostic code for the circuit with an FMI code. The FMI code will indicate whether the voltage is high or low.Short Circuit Between Two Voltage Sources - Can result in a voltage that should not be present. This type of short in an ECM output circuit can create uncontrolled machine movement. This type of short on an ECM input circuit can cause machine functions not to operate when requested. The ECM will detect these conditions and can activate a diagnostic code for the circuit. Reference: The machine Electrical SchematicTEST FOR A SHORT CIRCUIT
Identify the connectors and the wire numbers of the suspect circuits.
Turn off the key start switch and the disconnect switch.
Disconnect the component and the ECM from the wiring harness.
At the harness connector for the ECM, place one of the multimeter probes on the contact of the suspect circuit wire.
Use the other probe to check the resistance between the suspect circuit wire and frame ground. Also, check all of the other contacts that are used in the connector for the ECM.
While observing the multimeter measurement, wiggle the harness and harness connectors that of the circuit. Expected Result: The resistance does not indicate a short.OK - The resistance does not indicate a short. An intermittent short circuit could still be causing a problem.NOT OK - One or more of the resistance measurements indicates a short. The short is between the suspected circuit wire and the lowest resistance measurement.ISOLATING THE LOCATION OF THE SHORT CIRCUITWhen a short circuit is present, the short must be found and repaired.Perform the troubleshooting procedure for the specific diagnostic code that is activated. The procedure could help isolate the short location.When the harness is suspected, examine the circuit on the machine Electrical Schematic. Starting at the ECM:
Identify and locate each harness connector in the circuit.
One at a time, disconnect each connector.
Inspect the pins and the sockets on the male and female connector. Verify that all of the contacts are securely installed in the connector body. Ensure that the contacts are clean and in good condition.
Use a calibrated multimeter to measure resistance between the suspect wire and frame ground or the wire with the low resistance. While observing the multimeter, wiggle the connector and harness to check for intermittent short circuits. Perform this