SUPPORT 9P5708 - Caterpillar

Illustration 2 g03416708
Brake Pedal Limit Switch (1) Common Terminal (to 10 amp "Secondary Brake" fuse ) (2) Normal Open Terminal (to ECM) (3) Normal Closed Terminal (not used)
At the machine harness, measure the voltage between the normal closed contact (3) and frame ground. Expected Result:The voltage should be at + battery voltage and greater than 22 VDC. Results:
OK - The voltage is greater than 22 VDC. Proceed to Test Step 2.
NOT OK - The voltage is not greater than 22 VDC. Repair: Check the 10 amp "Secondary Brake" fuse # 19, located in right access panel, under the dash. If fuse is good, check for an open circuit or short circuit in wire (198-RD) from the fuse for the dump valve to the switch. Repair the cause of the open circuit or the short circuit. STOPTest Step 2. CHECK THE OPERATION OF THE SWITCH
Table 1
Left Brake Pedal Switch Circuit    
Switch State ECM Contact No.
Switch Term. & Wire No    Display Status    
Not Activated     J2-3 N/O     N/O (1)
G730-PK     O (2)    
Activated     J2-3 N/O     N/O
G730-PK     C (3)    
( 1 ) N/O = Normally Open.
( 2 ) O = Open
( 3 ) C = Closed (at battery voltage when machine is parked and engine is running)Note: With the machine "On", the state of the left service brake pedal switch should change from "O" to "C" when the left brake is depressed to the end of travel. If the display does not change from "O" to "C", the switch may be out of adjustment or the switch has failed. Manually adjust the switch in order to change the state of the switch when the pedal is fully pressed. If the state of the switch does not change when the switch is adjusted, continue with this Test Step.
Turn the key start switch to the OFF position.
The machine harness remains disconnected from the switch.
At the switch, measure the resistance between the common contact and the normally open contact (2) . See table 1.
Measure the resistance while the switch is activated. Also, measure the resistance while the switch is not activated. Expected Result:The measurement is the same value as the value in table 1. Results:
OK - The value that is measured matches the value that is listed in the table. The left brake pedal switch is good. Proceed to Test Step 5.
NOT OK - The value that is measured does not match the value that is listed in the table. Repair: The left brake pedal switch has failed. Replace the switch. Note: When installing a new brake switch, apply thread adhesive to the mounting screws and ensure that lock washers are used to mount the switch. STOPTest Step 3. CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND
The machine harness remains disconnected from the switch.
Turn the key start switch to the OFF position.
Disconnect the machine harness from the left secondary brake dump solenoid.
Disconnect the machine harness connectors J1 and J2 from the ECM.
At machine harness connector