Intermittent and Poor Connections
Most intermittents are caused by faulty electrical connections or wiring.
Occasionally a sticking relay or solenoid can also cause an intermittent failure.
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. |
| • | Exposure of terminals to moisture and dirt causing improper terminal
orientation with the component or mating connector. |
| • | Improperly formed or damaged terminals. |
| • | Check all connector terminals in problem circuits in order to
ensure good contact tension. Use a corresponding mating terminal to check
for proper tension. Refer to Checking Terminal Contact in this section 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. |
| • | This causes 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 Repairs and Connector Repairs.
Checking Terminal Contact
When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630
series terminals (refer to the J 38125-A Terminal Repair Kit or the
J 38125-4 Instruction Manual for terminal identification), it is important
to check terminal contact between a connector and component, or between in-line
connectors, before replacing a suspect component. When diagnosing an electrical
system that utilizes Metri-Pak
Frequently, a diagnostic chart leads to a step that reads: Check for
poor connection. Mating terminals must be inspected to assure 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 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.
Follow the procedure below to check terminal contact.
- Separate the connector halves. Refer to the J 38125-A Terminal
Repair Kit or the J 38125-4 instruction manual.
- Inspect the connector halves for contamination. Contamination
will result in a white or green build- up within the connector body or between
terminals, causing high terminal resistance, intermittent contact, or an open
circuit. An underhood or underbody connector that shows signs of contamination
should be replaced in its entirety: terminals, seals, and connector body.
- Using an equivalent male terminal from the J 38125-A Terminal
Repair Kit, check the retention force is significantly different between the
two female terminals, replace the female terminal in question (refer to the
J 38125- A TerminalRepair Kit.
If a visual (physical) check does not reveal the cause of the problem,
you may have the vehicle with a DMM connected to the suspected circuit. An
abnormal voltage reading when the problem occurs indicates the problem may
be in that circuit.
