GM Service Manual Online
For 1990-2009 cars only

Most intermittents are caused by faulty electrical connections or wiring. Some items to check are:

    • 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 in Electrical Diagnosis for the specific procedure.
    • J 35616 Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure 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 in Electrical Diagnosis for the specific procedure.
    • Poor terminal to wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the 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 or parts of the vehicle.
    • Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only one or two strands of a multi-strand type wire are intact, resistance could be far too high.

To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair detailed in Wiring Repair in Electrical Diagnosis.