259D Compact Track Loader – Electrical Connector – Inspect

ReferenceSpecial Instruction, SEHS9615, "Servicing DT Connectors".

ReferenceSpecial Instruction, REHS0148, "Listing Of Deutsch Connector Components"

ReferenceSpecial Instruction, SEHS9065, "Use Of CE Connector Tools".

ReferenceService Magazine, SEPD034227 January 97, "Field Repair Of Single Wire Breaks In Harnesses (Sealed Splice)".

ReferenceService Magazine, SEPD037128 July 97, "Protection Of Unsealed Electrical Terminations For Machines In Corrosive Applications".

ReferenceService Magazine, SEPD047324 May 99, "New DT Connector Plugs With Improved Seal Retention".

ReferenceService Magazine, SEPD054509 October 00, "Dielectric Grease Should Not Be Used In Electrical Connectors".

ReferencePocket Guide, SEBD0402, "Guidelines For Routing And Installing Wire Harness Assemblies".

This information will assist in detecting problems with connectors and wiring. If a problem is found, correct the condition and verify that the problem is resolved.

Disconnecting and reconnecting connectors sometimes resolve intermittent electrical problems. Check for diagnostic codes immediately before disconnecting a connector. Also check for diagnostic codes after reconnecting the connector. If the status of a diagnostic code changed due to disconnecting and reconnecting a connector, the likely reasons are:

  • Loose terminals

  • Improperly crimped terminals

  • Moisture

  • Corrosion

  • Inadequate mating of a connection


  • Use a 1U-5804 Crimp Tool (12-GA TO 18-GA) to service Deutsch HD and DT connectors. Never solder the terminals onto the wires. See Tool Operating Manual, SEHS9615, "Servicing Deutsch HD and DT Style Connectors".

  • Use a 147-6456 Wedge Removal Tool to remove wedges from DT connectors. Never use a screwdriver to pry a wedge from a connector.

  • Use a breakout harness for a voltmeter probe or a test light. Never break the insulation of a wire to access to a circuit for measurements.

  • If a wire is cut, always install a new terminal for the repair.


Check Connectors for Moisture and Corrosion

Illustration 1g01960167

(1) Former seal design

(2) Current seal design

Illustration 2g01960176

(3) Seal for a three-pin connector (typical example)

The plug end of the DT connector has a seal at the mating end of the connector. This replaceable seal has been improved on black connectors to help prevent slipping. This improvement will help keep moisture and dirt from entering the connector.

The current seal design (2) is not interchangeable with the former design (1). The receptacle has also changed to the new colors.

  1. Inspect all wiring harnesses. Ensure that the routing of the wiring harness allows the wires to enter the face of each connector at a perpendicular angle. Otherwise, the wire will deform the seal bore. This deformation will create a path for the entrance of moisture. Verify that the seals for the wires are sealing correctly.

  1. Disconnect the suspect connector and inspect the connector seal. Ensure that the seals are in good condition. If necessary, replace the connector.

  1. Thoroughly inspect the connectors for evidence of moisture entry.

    Some minor seal abrasion on connector seals is normal. Minor seal abrasion will not allow the entry of moisture. If moisture or corrosion is evident in the connector, the source of the moisture entry must be corrected. If the source of the moisture entry is not repaired, the problem will recur. Simply drying the connector will not fix the problem. Check the following items for the possible moisture entry path:

    • Missing seals

    • Improperly installed seals

    • Nicks in exposed insulation

    • Improperly mated connectors

    Moisture can also travel to a connector through the inside of a wire. If moisture is found in a connector, thoroughly check the connector harness for damage. Also check other connectors that share the harness for moisture.

  1. Repair or replace any bad connector. Correct any moisture problems.

Check the Wire Insulation for Damage

  1. Carefully inspect each wire for signs of abrasion, of nicks, and of cuts. Inspect the wires for the following conditions:

    • Exposed insulation

    • Rubbing of a wire against the chassis

    • Rubbing of a wire against a sharp point

  1. Check all of the wiring harness fasteners to verify that the harness is properly secured. Check all of the fasteners to verify that the harness is not compressed. Pull back the harness sleeves to check for a flattened portion of wire. A fastener that has been overtightened will flatten the harness. This damages the wires that are inside the harness.

  1. Repair or replace any wire with insulation damage.

Inspect the Connector Terminals

Visually inspect each terminal in the connector.

  1. Verify that the terminals are not corroded.

  1. Verify that the terminals are not damaged.

  1. Verify that the terminals are properly aligned in the connector.

  1. Verify that the terminals are properly located in the connector.

  1. Replace any bad terminal.

Perform a Pull Test on Each Wire Terminal Connection

Illustration 3g01625756

  1. Ensure that the locking wedge for the connector is installed properly. Terminals cannot be retained inside the connector if the locking wedge is not installed properly.

  1. Perform the 45 N (10 lb) pull test on each wire.

    Each terminal and each connector should easily withstand 45 N (10 lb) of tension and each wire should remain in the connector body. This test checks whether the wire was properly crimped in the terminal and whether the terminal was properly inserted into the connector.

  1. Replace any bad terminals.

Check Individual Pin Retention into the Socket

Inspect pin retention.

  1. Verify that the sockets provide good retention for the pins.

  1. Disconnect the harness. Insert a new pin into each socket one at a time to check for a good grip on the pin by the socket.

  1. Replace any bad pins or sockets.

Check the Locking Mechanism of the Connectors

  1. Ensure that the connectors lock properly.

  1. Lock the connectors, ensure that the two halves cannot be pulled apart.

  1. Verify that the latch tab of the connector is properly latched.

  1. Verify that the latch tab of the connector returns to the locked position.

  1. Replace any bad connectors.

Perform the Wiggle Test with Caterpillar Electronic Technician (Cat ET)

  1. Select the wiggle test from the diagnostic tests on Cat ET.

  1. Choose the appropriate group of parameters to monitor.

  1. Press the "Start" button.

  1. Wiggle the wiring harness to reproduce intermittent problems.

    If an intermittent problem exists, the status will be highlighted and an audible beep will be heard.

  1. Repair or replace any loose connections.

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