How to Check Terminals
SERVICE INFORMATYION FOR ELECTRICAL INCIDENT
HOW TO PROBE CONNECTORS
Connector damage and an intermittent connection can result from improperly probing of the connector during circuit checks. The probe of a Digital Multimeter (DMM) may not correctly fit the connector cavity. To correctly probe the connector, follow the procedures below using a "T" pin. For the best contact grasp the "T" pin using an alligator clip.
PROBING FROM HARNESS SIDE
Standard type (not waterproof type) connector should be probed from harness side with "T" pin.
^ If the connector has a rear cover such as a ECM (Engine control Module) connector, remove the rear cover before probing the terminal.
^ Do not probe waterproof connector from harness side. Damage to the seal between wire and connector may result.
PROBING FROM TERMINAL SIDE
Female Terminals
^ There is a small notch above each female terminal. Probe each terminal with the "T" pin through the notch.
Do not insert any object other than the same type male terminal into female terminal.
^ Some connectors do not have a notch above each terminal. To probe each terminal, remove the connector retainer to make contact space for probing
Male Terminals
Carefully probe the contact surface of each terminal using a "T" pin.
Do not bend terminal.
HOW TO CHECK ENLARGED CONTACT SPRING OF TERMINAL
An enlarged contact spring of a terminal may create intermittent signals in the circuit.
If the intermittent open circuit occurs, follow the procedure below to inspect for open wires and enlarged contact spring of female terminal.
1. Assemble a male terminal and approx. 10 cm (3.9 in) of wire.
Use a male terminal which matches the female terminal.
2. Disconnect the suspected faulty connector and hold it terminal side up.
3. While holding the wire of the male terminal, try to insert the male terminal into the female terminal.
Do not force the male terminal into the female terminal with your hands.
4. While moving the connector, check whether the male terminal can be easily inserted or not.
^ If the male terminal can be easily inserted into the female terminal, replace the female terminal.
TERMINAL LOCK INSPECTION
Check for unlocked terminals by pulling wire at the end of connector.
An unlocked terminal may create intermittent signals in the circuit.
WATERPROOF CONNECTOR INSPECTION
If water enters the connector, it can short interior circuits. This may lead to intermittent problems.
Check the following items to maintain the original waterproof characteristics.
RUBBER SEAL INSPECTION
^ Most waterproof connectors are provided with a rubber seal between the male and female connectors. If the seal is missing, the waterproof performance may not meet specifications.
^ The rubber seal may come off when connectors are disconnected. Whenever connectors are reconnected, make sure the rubber seal is properly installed on either side of male or female connector.
WIRE SEAL INSPECTION
The wire seal must be installed on the wire insertion area of a waterproof connector. Be sure that the seal is installed properly.
CONNECTOR AND TERMINAL PIN KIT
Use the connector and terminal pin kit listed below when replacing connectors or terminals.
The connector and terminal pin kit contains some of the most commonly used INFINITI connectors and terminals.
BEHIND INSTRUMENT PANEL
Improperly routed or improperly clamped harness can become pinched during accessory installation. Vehicle vibration can aggravate a harness which is routed along a bracket or near a screw behind or below the dash.
COLD OR HOT START UP
Electrical Load Test:
On some occasions an electrical incident may occur only when the car is started cold. Or it may occur when the car is restarted hot shortly after being turned OFF. In these cases you may have to keep the car overnight to make a proper diagnosis.
ELECTRICAL LOAD
The incident may be electrical load sensitive. Perform diagnosis with all accessories (including A/C, rear window defogger, radio, fog lamps) turned on.
ENGINE COMPARTMENT
There are several reasons a vehicle or engine vibration could cause an electrical complaint. Some of the things to check for are:
A. Connectors which are inaccessible for diagnosis probing.
B. Connectors which may not fully be seated.
C. Wiring harness which are not long enough and are being stressed during engine vibrations or rocking.
D. Wires laying across brackets or moving components.
E. Loose, dirty or corroded ground wires.
F. Wires routed too close to hot components.
To inspect components under the hood, start by verifying the integrity of ground connections.First check that the system is properly grounded. Then check for loose connection by gently shaking the wiring or components as previously explained. Using the wiring diagrams inspect the wiring for continuity.
FREEZING
The customer may indicate the incident goes away after the car warms up (winter time). In such cases the cause could be related to water freezing somewhere in the wiring/electrical system.
There are two methods to check for this. The first is to arrange for the owner to leave his car overnight. Make sure it will get cold enough to demonstrate his complaint. Leave the car parked outside overnight. In the morning, do a quick and thorough diagnosis of those electrical components which could be affected.
The second method is to put the suspect component into a freezer long enough for any water to freeze. Reinstall the part into the car and check for the reoccurrence of the incident. If it occurs, repair or replace the component.
HEAT SENSITIVE
The owner's problem may occur during hot weather or after car has sat for a short time. In such cases you will want to check for a heat sensitive condition.
To determine if an electrical component is heat sensitive, heat the component with a heat gun or equivalent.
Do not heat components above 6O°C (14O°F).If incident occurs while heating the unit, either replace or properly insulate the component.
UNDER SEATING AREAS
An unclamped or loose harness can cause wiring to be pinched by seat components (such as slide guides) during vehicle vibration. If the wiring runs under seating areas inspect wire routing for possible damage or pinching.
VEHICLE VIBRATION
The problem may occur or become worse while driving on a rough road or when engine is vibrating (idle with A/C on). In such a case, you will want to check for a vibration related condition. Refer to the illustration below.
Connectors & harness
Determine which connectors and wiring harness would affect the electrical system you are inspecting.
Gently shake each connector and harness while monitoring the system for the incident you are trying to duplicate. This test may indicate a loose or poor electrical connection.
Hint: Connectors can be exposed to moisture. It is possible to get a thin film of corrosion on the connector terminals. A visual inspection may not reveal this without disconnecting the connector. If the problem occurs intermittently, perhaps the problem is caused by corrosion. It is a good idea to disconnect, inspect and clean the terminals on related connectors in the system.
Sensors & relays
Gently apply a slight vibration to sensors and relays in the system you are inspecting.
This test may indicate a loose or poorly mounted sensor or relay.
Incident Simulation Tests:
Tester probe
When probing a connector it is possible to enlarge the contact spring opening. If this occurs it may create an intermittent signal in the circuit. When probing a connector, use care not to enlarge the opening. The probe of the Digital Multimeter (DMM) may not fit into the connector cavity. In such cases make an extension of a "T" pin and back probe the connector with it. Most DMMs have accessory alligator clips. Slide these over the probe to allow clipping the "T" pin for a better contact. If you have any difficulty probing a terminal, inspect the terminal. Ensure you have not accidentally opened the contact spring or pulled a wire loose.
WATER INTRUSION
The incident may occur only during high humidity or in rainy/snowy weather. In such cases the incident could be caused by water intrusion on an electrical part. This can be simulated by soaking the car or running it through a car wash.
Do not spray water directly on any electrical components.