Intermittent Problems

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 which 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. Use a corresponding mating terminal to check for proper tension. Refer to "Checking Terminal Contact" 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 occurs. as well as giving an idea of whether contact tension is sufficient. if contact tension seems incorrect, refer to "Checking Terminal Contact" for specifics.

^ Poor terminal-to-wire connection. Checking this requires removing the terminal from the connector body as outlined in Diagnostic Aids. Some conditions which fail under this description are poor crimps, poor solder Joints, crimping over wire insulation rather than wire itself, corrosion in the wire-to-terminal contact area, etc.

^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring parts of the vehicle.

^ Wiring broken inside the insulation. This condition could cause a continuity check or voltage check to show a good circuit; however, if only 1 or 2 strands of a multi-strand-type wire are Intact, the system may not operate properly.

To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined in Diagnostic Aids.

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 connector and component, or between in-line connectors, before replacing a suspect component.

Frequently, a diagnostic chart leads to a step that reads "Check for 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 underhood or underbody 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 contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. Refer to Diagnostic Aids for repair procedures.