HARNESS INSPECTION PROCEDURES
Most electrical problems are caused by poor connections. The following procedure will assist in detecting problems
with connectors and wiring. If a problem is found, correct the condition and verify that the problem is resolved.
Intermittent electrical problems are sometimes resolved by disconnecting and reconnecting connectors. It is very
important to 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 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:
1. Always use the correct tools designed for each connector. Never solder the terminals onto the wires.
2. 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.
3. If a wire is cut, always install a new terminal as part of the repair.
The connection or disconnection of any electrical equipment and the disconnection of any
electrical equipment may cause an explosion hazard which may result in injury or death. Do not
connect any electrical equipment or disconnect any electrical equipment in an explosive
Moisture and Corrosion Inspection
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 and will create a path for
the entrance of moisture. Verify that the seals for the wires are sealing properly.
2. Ensure 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.
3. Disconnect the suspect connector and inspect the connector seal. Ensure that the seals are in good
condition. If necessary, replace the connector.
4. Thoroughly inspect the connectors for evidence of moisture.
Minor abrasion on connector seals is normal and will not allow the entry of moisture.
5. If moisture or corrosion is evident in the connector, the source of the moisture must be found and repaired. If
the source of the moisture is not repaired, the problem will recur. Simply drying the connector will not fix the
problem. Check the following items for possible moisture entry.
a. Missing or improperly installed seals.
b. Nicks in exposed insulation
Improperly mated connectors