How To Connect 4-Way Flat Vehicle Connector To 7-Way on Trailer


I have a 4-flat on my vehicle. I want to connect to 7-round on my trailer. Do you have a cable or a coiled-cable for this? Thanks in advance!


Expert Reply:

To connect your vehicle that has a 4-Way flat connector to your trailer that has a 7-Way connector, you will need to install a 7-Way on the rear of your vehicle. If you just want or need the tail light functions to operate on your trailer you will just need Adapter 4 Pole to 7 Pole, part # 37185. If you need the complete 7-Way wiring to operate, you will need Brake Controller 7 & 4 Way Installation Kit, part # ETBC7.

The 4-Way on part # ETBC7 will plug into the 4-Way on your vehicle and then you will need to connect the remaining wires. The White wire is the ground and should be connected to the frame of vehicle. The Black wire will be connected to the Black wire inside the duplex cable and ran to front of vehicle and connected to the battery via included 40 amp circuit breaker. The Blue wire will be connected to the White wire inside the duplex cable, and ran to the front of the vehicle and later will be connected to the brake controller. The Purple wire can be connected to the reverse lights if trailer has reverse lights or can be taped off and tied out of the way if not being used.

Installing a 7-Way on your vehicle will allow you to install a brake controller on your vehicle to activate the brakes on the trailer if equipped or for future towing needs. Part # ETBC7, will allow you to have both a 4-Way and 7-Way on the back of your vehicle.

If you need a brake controller, email me back and I would be happy to recommend one. Also if you need a brake controller, let me know the year, make and model of your vehicle as some vehicles use a plug-in harness to install brake controller.

I have linked an FAQ on wiring and on installing part # ETBC7 that you may find as a good reference.

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