Checking Terminal Contact

When diagnosing an electrical system that utilizes any Metri-Pack or 56 in series terminals (refer to the J 38125-B 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 suspected component. Frequently, a diagnostic 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, damage to the connector itself or exposing the terminals to moisture and dirt, can cause contamination. Contamination, usually in the 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.
1. Separate the connector halves. Refer to the J 38125-B Terminal Repair Kit or the J 38125-4 instruction manual.
2. Visually inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals. This causes 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.
3. Using an equivalent male terminal from the J 38125-B Terminal Repair Kit, check that retention force is significantly different between a known good terminal and a suspect terminal. Replace the female terminal in question (refer to the J 38125-B Terminal Repair Kit.)

If a visual physical check does not reveal the cause of the problem, connect a DMM to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit.