SWITCH AS-ROTARY 3T6655 - Caterpillar

System Operation Description:The electrical power for the engine comes through a 63 amp circuit breaker, the Engine Control Switch (ECS), and the Electronic Control Modules (ECM). The engine has a Primary Electronic Control Module (ECM) and a Secondary Electronic Control Module (ECM). A signal is provided to the ECM that senses the position of the Engine Control Switch (ECS). When the ECM senses battery voltage on this input, the ECM will power up. If the voltage is removed from the input, the ECM will power down. If the remote start switch is in the start position and the remote emergency stop switch is not activated, the engine will start when the ECS is in the AUTO position. The ECM will power up when the ECS is in the AUTO, START, or STOP positions.Battery voltage is supplied to the ECM through the circuit breaker for the ECM and the ECM relay. The ECM relay is energized when the ECS is in the AUTO, START, or STOP positions and the emergency stop button is not activated.When the emergency stop switch is activated, power is removed from the coils of the ECM relays. The contacts of the ECM relay open removing the Battery power to the ECM. A relay performs an emergency lockout function that prevents the ECM from powering up until the ECS is turned to the OFF position.The presence of two + Battery connections and two − Battery connections to the ECM reduce harness resistance. All of these connections must be complete in order to ensure proper engine operation.
Illustration 1 g00807932
Typical schematicNote: The Engine Control Switch (ECS) is mounted within an instrument panel that is located on the right side of the engine. The ECS is locked into the AUTO position with a pin. The pin must be removed in order to perform this test. After performing this test, ensure that the ECS is placed in the AUTO position and that the locking pin has been reinstalled.Test Step 1. Check for Connector Damage.
Verify that the circuit breakers are not tripped.
Turn the circuit breaker for the battery to the OFF position.
Turn the ECS to the OFF/RESET position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" 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:All connectors, pins, and sockets are coupled and/or inserted, and the harness and wiring should be free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are okay. Proceed to test step 2.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors or