GASKET 8N8156 - Caterpillar

Most electrical faults are caused by poor connections. The following procedure will assist in detecting faults with connectors and with wiring. If a fault is found, correct the condition and verify that the fault is resolved.Intermittent electrical faults are sometimes resolved by disconnecting and reconnecting connectors. Check for diagnostic codes immediately before you disconnect a connector. Also check for diagnostic codes after you reconnect the connector. If the status of a diagnostic code is changed due to disconnecting and reconnecting a connector, there are several possible reasons. The likely reasons are loose terminals, improperly crimped terminals, moisture, corrosion, and inadequate mating of a connection.Follow these guidelines:
Always use a 1U-5804 Crimp Tool to service Deutsch HD and DT connectors. Never solder the terminals onto the wires. Refer to "SEHS9615, Servicing Deutsch HD, and DT Style Connectors".
Always use a 147-6456 Wedge Removal Tool in order to remove wedges from DT connectors. Never use a screwdriver to pry a wedge from a connector.
Always use a breakout harness for a voltmeter probe or a test light. Never break the insulation of a wire in order to access to a circuit for measurements.
If a wire is cut, always install a new terminal for the repair.
Determine if the problem is intermittent. If the problem is intermittent, attempt to test the circuit before you disconnect any electrical connectors. The test will help identify the root cause of intermittent problems. The "Wiggle Test" on Caterpillar Electronic Technician (ET) may be able to test the circuit. Refer to the documentation that accompanies Cat ET. Perform the wiggle test on the circuit, when possible. Otherwise, continue with this procedure.Check Connectors for Moisture and Corrosion
Illustration 1 g01131211
Detail A illustrates the incorrect angle of wire entry into the connector. The wire should enter the connector at a perpendicular angle. (typical example)Inspect all the 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. The damaged seal will create a path for the entrance of moisture. Verify that the seals for the wires are sealing correctly.
Illustration 2 g01131276
Diagram for the installation of a connector plug (typical example) (1) Electronic Control Module (ECM) connector (2) Correctly inserted plug (3) Incorrectly inserted plugEnsure that the sealing plugs are in place. If any of the plugs are missing, replace the plug. Ensure that the plugs are inserted correctly into the connector.
Illustration 3 g01131019
Seal for a three-pin connector (typical example)
Illustration 4 g01131165
Seal for the ECM connector (typical example)Disconnect the suspect connector and inspect the connector seal. Ensure that the seal is in good condition. If necessary, replace the connector.Thoroughly inspect the connectors for evidence of moisture entry.Note: 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 found. The source of the moisture entry must be repaired. If the source of the moisture