Wiring Harness (Open Circuit) - Test
An open is a failure of an electrical circuit that results in no flow of electrical current. An open circuit is usually caused by failed electrical wires or a poor connection of electrical connectors. If an electrical wire or a connection is broken, the flow of electrical current through the circuit is interrupted. A normally closed circuit will have less than 5 ohms of resistance. The following procedure explains the test for an open circuit:
Reference: For a complete electrical schematic, refer to Electrical System Schematic for the machine that is being serviced.
TEST FOR AN OPEN CIRCUIT.
- Identify the connectors and the wire numbers of the suspect circuits. Use the Electrical System Schematic of the machine to identify the circuits.
- Turn the key start switch and the disconnect switch to the OFF position.
- Unplug the connectors from the PL102C module. Disconnect the suspect wire of the wiring harness from the machine harness.
- At one of the disconnected PL102C wire harness connections, place a jumper wire from the contact of the suspect wire to frame ground.
- At the other connector of the PL102C, use the multimeter probes to measure the resistance from the contact of the suspect wire to frame ground.
Expected Result: The resistance is less than 5 ohms.
OK - The resistance is less than 5 ohms. The harness circuit is correct.
Stop.
NOT OK - The resistance is greater than 5000 ohms. There is an open in the machine harness.
Repair: Repair the PL102C harness or replace the PL102C harness.
Stop.
Caterpillar Information System:
Product Link - PL102C Wiring Harness (Short Circuit) - Test
G3406 Engine Engine Operation
3406E, C-10 and C-12 On-highway Engines Injector Solenoid Circuit - Test
C11 and C13 Petroleum Engines Fan Drive
G3516B Engines ECM Status Indicator Output
12M Motor Grader Kingpin Bearings - Lubricate
C-10, C-12, C-15 and C-16 Industrial Engines Flash Codes
325D and 329D Excavators Air Conditioner/Cab Heater Filter (Recirculation) - Inspect/Replace
Electrical System for All Caterpillar Products Starting System
Electrical System for All Caterpillar Products Charging System
Electrical System for All Caterpillar Products Battery
G3516B Engines ECM Output Circuit (Starting Motor)
Product Link - PL102C Electrical Connector - Inspect
3406E and 3456 Generator Set Engines Replacing the ECM
3406E, C-10 and C-12 On-highway Engines Multi-Torque - Test
12M Motor Grader Engine Starting
3406E, C-10 and C-12 On-highway Engines Powertrain Data Link Circuit - Test
C11 and C13 Petroleum Engines Electric Starting Motor
3126B Petroleum Engine Connecting Rod
C27 PET GEN SET Electric Power Generation and C27 KNOCKDOWN K Petroleum Power Train Package Electrical System
3406E, C-10 and C-12 On-highway Engines PTO Switch Circuit - Test
C27 and C32 Industrial and Petroleum Engines Can Not Reach Top Engine RPM
C11 and C13 Engines Electronic Unit Injector Wiring
143H and 163H Motor Graders Wheel Bearing Oil (Front) - Change - If Equipped