1Pcs 4-Way Flat Trailer Wiring Tester 4 Pin Male and Female Trailer Tester with Bright Indicators, Double End Design 4 Pin Trailer Light Tester For Turn Signal Tail Lights Trouble Shooter. 1.4 Way Trailer Tester: Using this 4 pin trailer plug tester to confirm proper function of your vehicle’s trailer wiring harness, excellent for diagnosing trailer light issues, lets you know where in the system there is a problem instead of guessing; It also acts as a standard 4-Pin male and female trailer connector to connect standard 4-pin trailer wire.
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