3512B Marine Auxiliary Engine Caterpillar

Most electrical problems are caused by poor connections. The following procedure will assist in detecting problems due to connectors. If a problem is found in an electrical connector, repair the connector. Do NOT cut connector wires unless terminals are being replaced. Repair the connectors with a 1U-5804 Crimp Tool .

Intermittent electrical problems often disappear by disconnecting and reconnecting connectors. Check for diagnostic codes before disconnecting and connecting a connector. If a diagnostic code is generated due to disconnecting and reconnecting a connector, there are several possible reasons. The likely problems are loose or improperly crimped terminals, moisture, corrosion, or connectors not mated securely.

The following procedure will ensure the correct installation of pins and sockets in connectors:

• Do not solder the sockets and pins to the wires.

• Do not crimp any more than one wire into a socket or into a pin. Refer to Illustration 3. Sockets and pins should be crimped on the wires. Use the 1U-5804 Crimp Tool for 12 - 18 gauge wire.

• Unused slots for sockets and pins must be filled with sealing plugs in order to ensure that the connector is sealed.

• Sealing plugs should be installed on the back side of the connector. Wires are inserted into the connector from the back side.

• The sealing plugs that are installed in unused slots must seal correctly. The plug rests against the seal face. Do not permit the large end of the plug to go past the seal face. Refer to Illustration 4 for correct installation of plugs.

Illustration 1	g00889323

Illustration 2	g00720332
Harness

Illustration 3	g00721340

Illustration 4	g00690571
Deutsch Sealing Plug

Illustration 5	g00690572
Deutsch Contact Terminals

Test Step 1. Check the Locking of the DT Connector (Deutsch) and Check the Lock Ring of the HD Style Connector (Deutsch).

1. Ensure that the connector is properly locked. Also ensure that the two halves of the connector can not be pulled apart.

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

Expected Result:

The connector will securely lock. The connector and the locking mechanism are without cracks or without breaks.

Results:

• OK - The connector will lock securely. The connector and the locking mechanism are without cracks or without breaks. The connector is okay. Proceed to test step 2.

• Not OK - The connector will not securely lock or the connector and the locking mechanism have cracks or breaks. The connector needs repair.

  Repair: Repair the connector or replace the connector, as required. Refer to Special Instruction, SEHS9615, "Servicing DT Connectors". Refer to Special Instruction, SEHS9065, "Use of CE/VE Connector Tools".Verify that the repair eliminates the problem.

  Stop.

Test Step 2. Check the Allen Head Screw on the Connector for the Electronic Control Module (ECM).

1. Ensure that the allen head screw is properly tightened. Be careful not to overtighten the screw and break the screw.

2. Do not exceed 2.25 N·m (20 lb in) of torque on the allen head screw.

Expected Result:

The ECM connector is secure and the allen head screw is properly torqued.

Results:

• OK - The ECM connector is secure and the allen head screw is properly torqued. Proceed to test step 3.

• Not OK - The ECM connector or allen head screw need repair.

  Repair: Repair the connector or replace the connector, as required. Refer to Special Instruction, SEHS9615, "Servicing DT Connectors". Refer to Special Instruction, SEHS9065, "Use of CE/VE Connector Tools".Verify that the repair eliminates the problem.

  Stop.

Test Step 3. Perform a Pull Test on each Wire Terminal Connection.

1. Each terminal and each connector should easily withstand 45 N (10 lb) of pull 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.

2. The DT connectors use an orange wedge to lock the terminals in place. Ensure that the orange wedge is not missing and that the orange wedge is installed properly on the DT connectors.

   Note: Always use a crimp tool in order to terminate wires. Do not solder terminals. Use the 1U-5804 Crimp Tool .

Expected Result:

Each terminal and each connector easily withstands 45 N (10 lb) of pull and each wire remains in the connector body.

Results:

• OK - The connector and the terminals withstand the pull test. Proceed to test step 4.

• Not OK - The connectors and/or the terminals fail the pull test. The connectors and/or terminals need repair.

  Repair: Repair the terminals and/or replace the terminals, as required. Refer to Special Instruction, SEHS9615, "Servicing DT Connectors". Refer to Special Instruction, SEHS9065, "Use of CE/VE Connector Tools".Verify that the repair eliminates the problem.

  Stop.

Test Step 4. Monitor the Caterpillar Electronic Technician (ET) while the Wiring and the Connectors are Being Pulled.

1. If there is an active diagnostic code that pertains to the circuit, perform the following test:

   Monitor the active diagnostic code screen on the Cat ET while all the harnesses and the connectors that connect to the component with the active diagnostic code are pulled. If the harness is being pulled and the active diagnostic code disappears, there is a problem in the wiring or the connector.

2. If there are no active diagnostic codes that pertain to the circuit, perform the following test:

   Monitor the status screen on the Cat ET for the suspect component while the harnesses are being pulled. If the harness is being pulled and the reading changes erratically, there is a problem in the wiring or the connector.

3. If there are no active diagnostic codes and the operator is complaining about speed burps or power cutouts, perform the following test:

   Run the engine. Listen for speed burps or power cutouts while the wiring or the connectors are pulled. If the harness is being pulled and the engine has a speed burp or a power cutout, there could be a problem in the wiring or in the connector.

Expected Result:

The problem appears to be external to the harnesses and to the connectors. Pulling on the harness and the connectors has no effect on the active diagnostic code, on the component status, or on the engine performance.

Results:

• OK - There was no change in the active diagnostic code, in the component status, or in the engine performance. Proceed to test step 5.

• Not OK - There was a change in the active diagnostic code, in the component status, or in the engine performance.

  Repair: Repair the terminals and/or replace the terminals, as required. Refer to Special Instruction, SEHS9615, "Servicing DT Connectors". Refer to Special Instruction, SEHS9065, "Use of CE/VE Connector Tools".Verify that the repair eliminates the problem.

  Stop.

Test Step 5. Check the Wires for Nicks in the Insulation or Abrasion.

1. Carefully inspect each wire for signs of abrasion, nicks, or cuts.

   The following areas are locations that should be checked:

   • Exposed insulation

   • Points of rubbing wire against the engine

   • Points of rubbing wire against a sharp point

2. Check all of the hold down clamps for the harness in order to verify that the harness is properly clamped. Also check all of the hold down clamps for the harness in order to verify that the harness is not compressed by the clamp. Pull back the harness sleeves in order to check for a flattened portion of wire. The flattened portion of wire is caused by the clamp that holds the harness.

Expected Result:

The wires are free of abrasion, of nicks, or of cuts and the harness is properly clamped.

Results:

• OK - The wires are free of abrasion, of nicks, or of cuts and the harness is properly clamped. Proceed to test step 6.

• Not OK - An inspection of the wiring found a problem. The wires are not free of abrasion, of nicks, or of cuts and/or the harness is not properly clamped.

  Repair: Repair the wires or replace the wires, as required.Verify that the repair eliminates the problem.

  Stop.

Test Step 6. Check the Connectors for Moisture or Corrosion.

1. Ensure that the connector seals and the white sealing plugs are in place. If any of the seals or plugs are missing, replace the seal or the plug. If necessary, replace the connector.

2. Check all of the wiring harnesses in order to verify that the harness does not make a sharp bend out of a connector. This will deform the connector seal and this will create a path for the entrance of moisture.

   Thoroughly inspect ECM Connectors J1/P1 and J2/P2 for evidence of moisture entry.

   Note: It is normal to see some minor seal abrasion on the ECM Connector seals. Minor seal abrasion will not allow the entry of moisture.

3. If moisture or corrosion is evident in the connector, the source of the moisture entry must be found. The source of the moisture entry must be repaired. If the source of the moisture entry is not repaired, the problem will reoccur. Simply drying the connector will not fix the problem. Likely paths for the entrance of moisture are illustrated in the following list:
   • Missing seals

   • Improperly installed seals

   • Nicks in exposed insulation

   • Improperly mated connectors

   Moisture can also travel from one connector through the inside of a wire to the ECM Connector. If moisture is found in the ECM connector, thoroughly check all connectors and wires on the harness that connect to the ECM. The ECM is not the source of the moisture. Do not replace an ECM if moisture is found in either ECM connector.

   Note: If corrosion is evident on the pins, sockets or the connector, use only denatured alcohol to remove the corrosion. Use a cotton swab or a soft brush to remove the corrosion. Do not use any cleaners that contain 1,1,1 trichloro-ethylene because 1,1,1 trichloro-ethylene may damage the connector.

Expected Result:

All of the connectors should be completely coupled and all of the seals should be completely inserted. The harness and the wiring should be free of corrosion, of abrasion or of pinch points.

Results:

• OK - All of the connectors are completely coupled and all of the seals are completely inserted. The harness and the wiring are free of corrosion, of abrasion or of pinch points. The connectors and wiring were okay. Proceed to test step 7.

• Not OK - All of the connectors are not completely coupled and all of the seals are not completely inserted. The harness and the wiring are not free of corrosion, of abrasion or of pinch points. The connectors and/or wiring were not okay.

  Repair: Repair the circuit. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem by running the engine for several minutes and by checking again for moisture. If moisture reappears, the moisture is wicking into the connector. Even if the moisture entry path is repaired, it may be necessary to replace the wires that have moisture. These wires may have moisture that is trapped inside the insulation. Verify that the repair eliminates the problem.

  Stop.

Test Step 7. Inspect the Connector Terminals.

1. Verify that the terminals are not damaged. Verify that the terminals are properly aligned in the connector. Verify that the terminals are properly located in the connector.

Expected Result:

The terminals are properly aligned and the terminals appear undamaged.

Results:

• OK - The terminals are properly aligned and the terminals appear undamaged. The terminals were okay. Proceed to test step 8.

• Not OK - A problem was found with the terminals. The terminals are not properly aligned and/or the terminals appear damaged.

  Repair: Repair the terminals and/or replace the terminals, as required. Refer to Special Instruction, SEHS9615, "Servicing DT Connectors". Refer to Special Instruction, SEHS9065, "Use of CE/VE Connector Tools".Verify that the repair eliminates the problem.

  Stop.

Test Step 8. Check the Individual Pin Retention into the Socket.

Note: This is especially important for intermittent problems.

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

2. Use a new socket. Insert the socket over each pin one at a time in order to check for a good grip on the pin by the socket. The pins are located on the mating side of the connector.

3. The contact terminal should stay connected when the connector is held in the position shown in Illustration 5. The contact terminal is the pin or the socket.

Expected Result:

The pins and the sockets appear to be okay.

Results:

• OK - The pins and the sockets are okay.

  Repair: Recheck the system for diagnostic codes.

  Stop.

• Not OK - A problem was found in the pins or sockets.

  Repair: Repair the terminals and/or replace the terminals. Refer to Special Instruction, SEHS9615, "Servicing DT Connectors". Refer to Special Instruction, SEHS9065, "Use of CE/VE Connector Tools".Verify that the repair eliminates the problem.

  Stop.