PLATE AS 3805263 - Caterpillar

Illustration 1 g00610621
Schematic Of The Rotor Raise/Lower Switch
Table 1
ECM Contact     Switch Contact     Wire Number     LOWER     HOLD     RAISE    
26     Lower     C741-GN     Ground (Return)     Open     Open    
30     Raise     C740-GY     Open     Open     Ground (Return)    
39     Return     840-GN     Ground (Return)     Ground (Return)     Ground (Return)    The switch has two inputs to the ECM. During normal operation, only one of the inputs is closed. The preceding chart shows the continuity of each switch circuit for the three positions of the switch. When a circuit is measured with a voltmeter, an open circuit will measure 5 DCV and a returned circuit will measure approximately 0 DCV. A failure is detected when the status of both inputs is both returned. A CID 046 FMI F12 diagnostic code is recorded when the status of both inputs is both returned The results of this diagnostic code are:
A category 2 warning is showing on the Computerized Monitoring System.
The rotor will not raise or lower in manual mode. The function will be restored only after the diagnostic code is no longer present and the rotor depth mode switch has been reset to the manual position. The possible causes of this diagnostic code are:
Return circuit (840-GN) is open.
Signal circuit 1 (C741-GN) is grounded.
Signal circuit 2 (C740-GY) is grounded.
Switch is faulty.
ECM is faulty (unlikely).Service Note: Ensure that the CID 046 FMI F12 is on-hold and that the diagnostic code is present (diagnostic code (fault) present indicator in ON). If the diagnostic code (fault) present indicator is OFF toggle the switch until it is in the position where the diagnostic code present indicator is ON.
Check The LOWER Circuit For Proper Operation. This step checks the continuity of the LOWER circuit in the machine harness and the switch.
Turn the key start switch to OFF.
Disconnect machine harness connector from the ECM.
At the machine harness connector for the ECM, check continuity from connector 26 (C741-GN) to connector 39 (switch return). Expected Result: With the switch in the LOWER position there should be CONTINUITY. With the switch in the RAISE and hold positions, there should be NO CONTINUITY.Results:
OK - Proceed to step 3.
NOT OK - The switch or the machine harness is faulty. Proceed to the next step.
Check The LOWER Circuit For Proper Operation. This step checks the continuity of the LOWER circuit at the switch.
At the switch, disconnect wire C741-GN from contact 1.
At the switch, check continuity from contact 1 to contact 2. Expected Result: With the switch in the LOWER position, there should be CONTINUITY. With the switch in the RAISE and hold positions, there should be NO CONTINUITY.Results:
OK - The machine harness is faulty. Either the LOWER circuit (C741-GN) or the return circuit (840-GN) is open; or the LOWER circuit (C741-GN) is grounded in the machine harness. Repair or replace the machine harness. STOP.
NOT OK - The switch is faulty. Replace the switch. STOP.
Check The