How to Locate Reverse Lamp Circuit to Install 7-way Trailer Connector on 2017 Jeep Grand Cherokee

Published 01/02/2020

Products Featured in This Question

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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$71.57

14 Gauge Primary Wire - Blue - per Foot

(47)

$0.55

Hook Probe Circuit Tester

(60)

$12.27

Question:

How/From where do I add the reverse light wire in the vehicle to 7-pole connector? Does the reverse wire need the electical amp/relay to avoid overloading? Thanks

asked by: Takao

Expert Reply:

The easiest place to access it is the harness feeding the taillight assembly. If possible, locate the wire feeding the reverse light bulb, and you can tap into it there, using a length of wire like # DW02414-1 (sold by the foot) long enough to reach the 7-way. No relay would be necessary.

If you can't easily narrow down which wire feeds the reverse lamps by sight you can use a circuit tester like # PTW2993. Have a helper hold down the brake pedal, then probe the harness feeding the taillight assembly. Make note of which wire shows voltage, this will be the brake lamp. Then, with the brake still applied shift the transmission in reverse and probe the remaining wires. The wire that shows voltage will be the reverse lamp circuit.

expert reply by: Mike L