Intermittent and Poor Conditions

Intermittents And Poor Connections
Most intermittent problems are caused by faulty electrical connections or wiring. When an intermittent failure is encountered, check suspect circuits for:

^ Poor mating of connector halves or terminals not fully seated in the connector body (backed out).

^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material that could impede proper terminal contact.

^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector.

^ improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Refer to Checking Terminal Contact below for the specific procedure.

^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter ensures that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. if contact tension seems incorrect, refer to Checking Terminal Contact below for specifics.

^ Poor terminal-to-wire connection. Checking this requires removing the terminal from the connector body. Refer to Repairing Connectors in Electrical Diagrams some conditions that fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, and corrosion in the wire.


Checking Terminal Contact
When diagnosing an electrical system that uses Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit J 38125-A instruction manual J 38125-4 for terminal identification), it is important to check terminal contact between a connector component, or between in-line connectors before replacing a suspect component.

Frequently, a diagnostic chart leads to a step that reads "Check for a proper connection." Mating terminals must be inspected to ensure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation.

Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in under hood or under body connectors, leads to terminal corrosion, causing an open circuit or an intermittently open circuit.

Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves, or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal connector tang, can result in poor terminal contact causing an open or intermittently open circuit.

Use the following procedure to check terminal contact:
1. Separate the connector halves. Refer to Terminal Repair Kit J 38125-A instruction manual J 38125-4.

2. Inspect the connector halves for contamination. Contamination results in a white or green buildup within the connector body or between terminals, causing high terminal resistance, intermittent contact, or an open circuit. An under hood or under body connector that shows signs of contamination should be replaced in its entirety; terminals, seals, and connector body.

3. Using an equivalent male terminal from the Terminal Repair Kit J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact requires a certain amount of force to separate the terminals.

4. Using an equivalent female terminal from the Terminal Repair Kit J 38125-A, compare the retention force of this terminal to the female terminal in question. if the retention force is significantly different between the two female terminals, replace the terminal in question using a terminal from the Terminal Repair Kit J 38125-A.

If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a DVM connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit.