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catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
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Experience:  Field service technician for CAT 19 years.
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Cat 247b2 what if no lights flashing L/H stick working but

Customer Question

Cat 247b2 what if no lights flashing L/H stick working but not R/H
Submitted: 1 year ago.
Category: Construction and Road Equipment
Expert:  catmastertech replied 1 year ago.

Hello,

Have you checked the door switch?

Please post the full machine serial number with your reply.

The post says you tried testing power to the right side. Where did you check? What were you testing? (Voltage, resistance or pressures?)

Customer: replied 1 year ago.
No door switch checked for voltage ser# ***** 5879
Expert:  catmastertech replied 1 year ago.

Thanks for the serial number.

I am assuming you check for voltage at the RH joystick solenoid, (Referred to as the Work Tool Control) and did not find any power to the solenoid.

If this is correct, follow the procedure below to locate the source of your problem.

Work Tool Does Not Function

System Operation Description:

The Interlock ECM will NOT engage the work tool pilot solenoid if problems exist with the parking brake switch or the work tool pilot solenoid.

Note: Use a jumper wire on machines that do NOT use a lockout switch for the work tool. The jumper wire is 165-0312 Wire Assembly . This jumper wire is fastened to the harness in place of the switch. The jumper must be connected in order to allow both the primary work tool and the auxiliary work tool to operate. (MOST MACHINES HAVE THIS SWITCH)

Test Step 1. CHECK THE FAULT INDICATORS

  1. Occupy the seat.

 

  1. Lower the armrest.

 

  1. Turn the key start switch to the ON position.

 

  1. Press and release the parking brake switch.

Expected Result:

The armrest indicator and the parking brake indicator should be off.

Results:

  • OK - The armrest indicator and the parking brake indicator are off. Proceed to Test Step 2.

     

  • NOT OK - The parking brake indicator remains on.

    Repair: See Troubleshooting, "Switch (Parking Brake)".

    STOP

Test Step 2. CHECK THE CIRCUIT OF THE WORK TOOL PILOT SOLENOID

  1. Turn the key start switch to the OFF position.

 

  1. Raise the cab. See Operation and Maintenance Manual, "Cab Tilting".

 

  1. Locate the interlock ECM. The interlock ECM is located on the left side of the machine beneath the access cover on the floor of the machine.

 

  1. Remove the wire harness from the ECM.

 

  1. Measure the resistance from contact 24 to contact 68 (wire P988-OR to wire 975-WH) of the wire harness connector.

Expected Result:

The resistance should be approximately 6 Ohms.

Results:

  • OK - The resistance is approximately 6 Ohms.

    Repair: ECM failure is unlikely. Reconnect all connections and visually inspect the wire harness. Verify that the diagnostic code still exists. If the diagnostic code still exists perform the Test Steps again.Prior to replacing an ECM, contact the Technical Communicator (TC) at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time and expense.
    If the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

    STOP

  • NOT OK - The resistance is not approximately 6 Ohms. Proceed to Test Step 3.

Test Step 3. CHECK THE RESISTANCE OF THE WORK TOOL PILOT SOLENOID

  1. Locate the work tool pilot solenoid.

 

  1. Disconnect the wire harness from the work tool pilot solenoid.

 

  1. Measure the resistance of the two wires on the work tool pilot solenoid.

Expected Result:

The resistance should be approximately 10.5 Ohms.

Results:

  • OK - The resistance is approximately 10.5 Ohms. Proceed to Test Step 4.

     

  • NOT OK - The resistance is not approximately 10.5 Ohms.

    Repair: The solenoid has failed. Replace the coil.

    STOP

Test Step 4. CHECK THE RESISTANCE OF THE WORK TOOL DETENT COIL

  1. Locate the work tool detent coil. The detent coil is located beneath the right-hand joystick. Remove the access panel in order to get to the connector.

 

  1. Disconnect the wire harness from the work tool detent coil .

 

  1. Measure the resistance of the two wires on the work tool detent coil.

Expected Result:

The nominal resistance for the work tool detent coil, at a temperature of 25° C (77° F), is 29 Ohms. (Approximately 54 to 60 Ohms is typical)

Results:

If you need more help or this guide requires further information, please post the results you have collected so far and the step you need assistance with.

I will be glad to help more.

  • OK - The coil resistance is within specification.

    Repair: The wire harness has failed. Repair the wire harness and/or the connector or replace the wire harness and/or the connector.

    STOP

  • NOT OK - The coil resistance is Not within specification.

    Repair: The work tool detent coil has failed. Replace the work tool detent coil.

    STOP

Customer: replied 1 year ago.
Removed floor access plate there are two ECM which one am I'm testing also is work tool solenoid by the stick or on aux pump?
Customer: replied 1 year ago.
Everything test ok so I'm assuming the ECM is bad?
Expert:  catmastertech replied 1 year ago.

The work tool solenoid is part of the Interlock ECM, I think it is on the left side of the machine. It will have fewer wires and it will have the correct wire numbers and colors in the proper pin terminals. The other ECM is the Auxiliary ECM and is used of attachments and high flow machines.

The work tool solenoid is on the bottom of the work tool joystick (pilot) valve.

The ECM is the last item to consider when troubleshooting. I always perform the testing twice to verify my results are exactly the same. If anything tests differently, I repeat the testing until I can get the same results twice. Then I feel confident I have found the root cause of the failure and will order the failed parts.

It is far more common to find wire damage or failed solenoid coils when testing the circuits.

If you do have another machine available, place this machine's ECM in it to see if the problem follows the ECM. Do not install a new or borrowed ECM in this machine in case it has a short and this could damage a the ECM.

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