2-Pin 7122-4129-90 / 7157-6420-80 / 7123-4129-90 Yazaki 9.5mm Unsealed Connector – High-Current Harness

Direct-fit replacement for Yazaki OEM part numbers 7122-4129-90 (male plug), 7157-6420-80 (connector body), and 7123-4129-90 (female socket), a 2-pin unsealed 9.5mm pitch connector set from the Yazaki high-current series. At 9.5mm pitch, this is one of the largest standard automotive connector formats – rated at up to 40A per pin for main power feed and battery circuit applications.

Key Specifications

• OEM Part Numbers: 7122-4129-90 (male) / 7157-6420-80 (body) / 7123-4129-90 (female)
• Pin Count: 2
• Terminal Pitch: 9.5mm
• Seal Type: Unsealed (for dry, protected environments)
• Wire Gauge: 12 AWG (4.0 mm²) recommended for full 40A capacity
• Wire Length: 5.5 inches (140 mm)
• Housing Material: PA66 glass-filled nylon
• Terminal Material: Copper alloy, tin-plated
• Current Rating: Up to 40A per pin
• Voltage Rating: 12V / 24V DC
• Package: 1 set (male + body + female with wire)

Yazaki 9.5mm Series – Part Number Logic

• 7122-XXXX-XX: Male plug housing (pin contacts)
• 7157-XXXX-XX: Connector body / housing shell
• 7123-XXXX-XX: Female socket housing (socket contacts)
• Last two digits (-90): Wire seal color / variant code

Applications

• Battery positive cable junction connector
• Alternator output harness connector
• Main relay output – high-current power distribution
• Starter motor main power feed
• Motorcycle main power harness junction
• High-draw accessory circuits (winch, compressor, inverter)

High-Current Connector Selection Guide

• 6.3mm Faston / Metri-Pack 630: 20A/pin – relays, fans
• 7.8mm Yazaki: 30A/pin – main power, alternator
• 9.5mm Yazaki (this): 40A/pin – battery, starter, main power feeds

Frequently Asked Questions

Q: What wire gauge should I use for a 40A circuit?
A: Use a minimum of 8 AWG (10.0 mm²) for 40A continuous load. For 30A circuits, 10 AWG (6.0 mm²) is acceptable. Undersized wire causes voltage drop and connector overheating at high current loads.

Q: What crimping tool is needed for 9.5mm Yazaki terminals?
A: Use a heavy-duty ratchet crimper rated for 8–12 AWG (4.0–10.0 mm²) – such as Engineer PA-20 or equivalent. Standard automotive crimpers are too small for 9.5mm terminals.

Package Contents

1 × 2-Pin Male Connector (7122-4129-90) with wire
1 × Connector Body (7157-6420-80)
1 × 2-Pin Female Connector (7123-4129-90) with wire and terminal inserts