SWITCH GP-MAGNETIC 1752322 - Caterpillar

The overspeed verify switch provides a way to check the system at 75 percent of the set point. The set point is 118 percent over the rated engine rpm. When the engine reaches the set point, the strategy for the overspeed is initiated. This action will test the shutoff system. The overspeed verify switch allows you to verify proper operation of the system.
Illustration 1 g01619419Test Step 1. Check for Connector Damage.
Turn the engine control to the OFF position.
Turn the breaker at the battery to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and pinch points. Expected Result:The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.Results:
OK - The connectors and wiring are okay. Proceed to test step 2.
Not OK - The connectors and/or wiring are not okay.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Switch status on ET.
Connect an Electronic Service Tool to the service tool connector.
Turn the breaker at the battery to the ON position.
Select the status screen on the ET.
Toggle the overspeed verify switch to the ON position. Toggle the overspeed verify switch to the OFF position. Toggle the overspeed verify switch to the ON position. Expected Result:The status of the overspeed verify switch changed in accordance with the switch position.Results:
OK - The status of the overspeed verify switch changed in accordance with the switch position.Repair: The overspeed verify switch and related circuitry is operating correctly.STOP
Not OK - The status of the overspeed verify switch did not change in accordance with the switch position. Proceed to test step 3.Test Step 3. Check the condition of the Overspeed Verify Switch.Note: Record switch wiring before removing wire for correct reconnection.
Disconnect the main power.
Turn the overspeed verify switch to the OFF position.
Remove the wires from the terminals on the overspeed verify switch.
Connect a voltmeter between the terminals on the overspeed verify switch.
Measure the resistance between the terminals on the overspeed verify switch.
Turn the overspeed verify switch to the ON position.
Measure the resistance between the two terminals on the overspeed verify switch.
Reconnect all wires. Expected Result:The resistance is be greater than 20,000 Ohms with the Overspeed Verify Switch in the OFF position. The resistance is less than 10 Ohms with the overspeed verify switch in the ON position.Results:
OK - The resistance measurements are okay. The problem is not with the overspeed verify switch. Proceed to test step 4.
Not OK - The resistance measurements are not okay. The Overspeed Verify Switch is not