TURBOCHARGER GP 5288390 - Caterpillar

Introduction
An open is a failure of an electrical circuit that results in no flow of electrical current. An open circuit is often 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.Required Tools
Table 1
Required Tools
Tool Qty Part No Description
C - - Digital Multimeter Gp Test Preparation
Move the machine to a hard, level surface.
Engage the parking brake and stop the engine.
Install the steering frame lock. Reference: Refer to Operation and Maintenance Manual, "Steering Frame Lock" for the machine being serviced.Test Procedure
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 disconnect switch and the key start switch to the OFF position.
Disconnect the component and the Electronic Control Module (ECM) from the wiring harness.
At one of the disconnected harness connections, place a jumper wire from the contact of the suspect wire to frame ground.
At the other connector of the machine harness, use Tooling (C) probes to measure resistance from the contact of the suspect wire to frame ground. Expected Result: The resistance is less than 5 ohms. YES - The resistance is less than 5 ohms. The harness circuit is correct.Stop. NO - The resistance is greater than 5 ohms. There is an open in the machine harness.Repair: Repair the machine harness or replace the machine harness.Stop.
Remove Tooling (C).
Remove the steering frame lock. Reference: Refer to Operation and Maintenance Manual, "Steering Frame Lock" for the machine being serviced.