4-Pin 12129565 Waterproof 2.8mm Female Connector – GM Metri-Pack 280 Series

Direct-fit replacement for GM OEM part number 12129565, a 4-pin waterproof 2.8mm pitch connector from the Metri-Pack 280 series. The Metri-Pack 280 is GM's workhorse connector family for medium-current automotive circuits – used across engine management, transmission, and body electrical systems on Chevrolet, Buick, GMC, Cadillac, and Pontiac platforms, as well as motorcycle and powersports harnesses.

Key Specifications

• OEM Part Number: 12129565
• Pin Count: 4
• Gender: Female (with wire)
• Terminal Pitch: 2.8mm (Metri-Pack 280 series)
• Wire Gauge: 18 AWG (0.5 mm²)
• Wire Length: 5.5 inches (140 mm)
• Waterproof Rating: IP68
• Housing Material: PA66 glass-filled nylon
• Terminal Material: Copper alloy, tin-plated
• Current Rating: Up to 13A per pin
• Operating Temperature: -40°C to +125°C

Metri-Pack 280 Series – Why 2.8mm?

The 2.8mm Metri-Pack 280 is GM's standard for medium-current circuits (up to 13A per pin). It is larger than the 1.5mm Micro-Pack (7.5A) but smaller than the 6.3mm Metri-Pack 630 (20A+). Common applications include:

• Fuel injector connectors (EV1 / EV6 style)
• Oxygen sensor harness connectors
• Idle air control (IAC) valve wiring
• Transmission range sensor connectors
• Motorcycle lighting and ignition circuits

Common Fault Codes Linked to 12129565 Connector Failure

• P0201–P0208 – Injector circuit open (corroded Metri-Pack 280 injector connector)
• P0131 / P0151 – O2 sensor circuit low voltage (open circuit at sensor connector)
• P0505 – IAC system malfunction (loose or corroded IAC connector)

Frequently Asked Questions

Q: Is 12129565 the same as the EV1 fuel injector connector?
A: The EV1 injector connector is a 2-pin Metri-Pack 280 variant. The 12129565 is a 4-pin version of the same 2.8mm series – same terminal size and pitch, different pin count and housing. Do not confuse the two.

Q: What crimping tool is needed for Metri-Pack 280 terminals?
A: GM recommends the Kent-Moore J-38125-6 or Delphi 12085271 ratchet crimper for 2.8mm Metri-Pack terminals. The Molex 63811-9600 is also widely used. Avoid non-ratchet crimpers – inconsistent crimp height causes intermittent contact resistance.

Q: How do I remove terminals from the 12129565 housing?
A: Use a Metri-Pack terminal removal tool (GM J-35616-B or equivalent flat-blade pick). Insert alongside the terminal, depress the locking lance, and pull the wire from the rear. Never pull the wire without releasing the lock.

Q: Can this connector be used on motorcycles?
A: Yes. The 2.8mm Metri-Pack 280 series is used on many motorcycle and powersports harnesses, particularly for lighting, ignition, and sensor circuits requiring up to 13A per pin.

Package Contents

1 × 4-Pin Female Connector (12129565) with 18 AWG wire and terminal insert