The 4-pin flat trailer connector is the standard lighting connector for small trailers, utility trailers, and boat trailers across North America. Conforming to SAE J1239, the 4-pin flat provides circuits for tail/running lights, left turn/brake, right turn/brake, and ground. The flat-blade design is universally recognized and available at every auto parts store, hardware store, and trailer supply shop. The connector uses simple flat-blade contacts that slide together and are secured with a spring-loaded dust cover on the vehicle side. While not waterproof (rated IP44 for splash protection), the 4-pin flat is protected against casual moisture by the dust cover. For any trailer under 80 inches wide that does not require electric brakes or auxiliary power, the 4-pin flat is the standard and legally required interface in most jurisdictions.
Specifications
Pin Count
4
Wire Gauge Range
18–14 AWG
Voltage Rating
12 VDC
Current Rating
20A continuous
IP Rating
IP44
Mating Cycles
1000
Operating Temp
-40°C to +85°C
Key Features
SAE J1239 standard for North American trailers
Four circuits: tails, left turn, right turn, ground
Universal flat-blade design recognized everywhere
Spring-loaded dust cover on vehicle-side connector
Available at virtually every auto parts store
Simple installation with basic crimp or solder tools
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