BOOM & BEARING AS 3908759 - Caterpillar

for an intermittent short circuit to a ground circuit and to another circuit in the machine harness that could cause the circuits to be distorted.
Refer to the connection diagram for the Motor ECM controlled transistor driver and feedback circuits at the beginning of this procedure. At the disconnected machine harness 70 pin control circuit connector for the Power Inverter, measure the resistance between each individual Motor ECM driver circuit contacts and each of the other contacts that are used on the 70 pin control circuit connector for the Power Inverter. While observing each resistance measurement, wiggle the harness connectors and wiggle the harness.
Measure the resistance between each individual Motor ECM feedback circuit contact and each of the other contacts that are used on the 70 pin control circuit connector for the Power Inverter. While observing each resistance measurement, wiggle the harness connectors and wiggle the harness.Expected Result:Each of the resistance measurements between the individual driver circuits and all of the other circuits in the Inverter connector are greater than 5000 ohms. Each of the resistance measurements between the individual feedback circuits and all of the other circuits in the Inverter connector are greater than 5000 ohms.Results:
OK - Each of the resistance measurements is greater than 5000 ohms at all times during the manipulation of the harness and the connectors. The resistance measurements are indicating that the motor transistor driver circuits and the feedback circuits are not shorted to another circuit in the machine harness. Proceed to Test Step 3.
NOT OK - At least one of the resistance measurements is less than 5000 ohms during the measurement or during the manipulation of the harness and the connectors. There is a short circuit or an intermittent short circuit in the machine harness. The short is between the transistor driver circuit or the transistor feedback circuit and another circuit in the machine harness.Repair: The machine harness that connects the J2 connectors for the Generator ECM and the Motor ECM to the Power Inverter 70 pin connector is not serviceable. This machine harness is a sealed harness. Replace the machine harness.Refer to the complete machine Electrical System Schematic