SEAL 8C3077 - Caterpillar

System Operation Description:Use the following procedure to troubleshoot the electrical system if a problem is suspected with the switch circuits or if another procedure has sent you here.The following switches may be used:
Maintenance clear switch (NO)
Torque limit switch (NO)
Ether starting aid switch (NO)
PTO interrupt switch (NC)
Remote shutdown switch (NO)
Intermediate engine speed switch (NO)
Overspeed verify switch (NO)
PTO enable switch (NO)
PTO ramp up switch (NO)
PTO ramp down switch (NO)Switch circuits may have problems such as faulty wiring, faulty switches, or faulty connectors.The switches are normally open or normally closed.
Illustration 1 g01434295
Schematic for the normally open switch and the normally closed switchTypical switch inputsTest Step 1. Check the Electrical Connectors and the Wiring
Remove electrical power from the Electronic Control module (ECM).
Illustration 2 g01428866
ECM (1) J1/P1 connectors (2) J2/P2 connectors
Thoroughly inspect the J1/P1 and the J2/P2 ECM connectors. Thoroughly inspect the connections for the suspect switch. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01428883
P1 terminals for the various switches (P1-13) Ether starting aid switch (P1-8) Remote shutdown switch (P1-24) Intermediate engine speed switch (P1-32) Overspeed verify switch (P1-20) PTO enable switch (P1-25) PTO ramp up switch or set switch (P1-15) PTO ramp down switch or resume switch
Illustration 4 g01428901
P2 terminals for the various switches (P2-31) Maintenance clear switch (P2-16) Torque limit switch (P2-26) PTO interrupt switch
Perform a 45 N (10 lb) pull test on each of the wires in the circuit for the suspect switch.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the allen head screw on the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
Check the harness and wiring for abrasions and for pinch points.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The wiring and connectors are OK. Proceed to Test Step 2.
Not OK - There is a problem with the wiring and/or a connector.Repair: Repair the wiring and/or the connector. Replace parts, if necessary. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.STOPTest Step 2. Test the Switch for Proper Operation
Disconnect the J1/P1 and the J2/P2 ECM connectors.
Refer to Table 1. Determine the terminal for the suspect switch.
Table 1
Terminals for the Switch Inputs    
Name of the Switch     ECM Terminals     Connector Terminals    
Maintenance clear switch     P2-31     12    
Torque limit switch     P2-16     2    
Ether starting aid switch     P1-13     38    
PTO interrupt switch     P2-26     19    
Remote shutdown switch     P1-8     27    
Intermediate engine speed switch     P1-24     28    
Overspeed verify switch     P1-32     40    
PTO enable switch     P1-20     29    
PTO ramp up switch or set switch     P1-25     30    
PTO ramp down switch or resume switch     P1-15     39    
Connect a meter lead to