Will Connecting 12-V Feed for ETBC7 and Powered Taillight Converter Harm Anything?

Question:

Hi e-trailer - I purchased a Redarc tow-pro and an ETBC7 kit from you in order to activate brakes on my camp trailer from my Nissan Rogue. Previously, on this vehicle I had installed a standard 4-way trailer harness for an earlier trailer. In that installation I did run a fused hot-wire connection directly from the battery back to the harness [as your page https://www.etrailer.com/faq-wiring-4-way.aspxinch indicates is sometimes necessary.] Im not sure if that was absolutely required or not, but thats what Ive got now. So -heres the question: the ETBC7 kit also calls for running a fused hot-wire connection from the battery to the rear of the car to connect on the 7 prong connector. Since the 4-way connector already has the hot wire - is this a potential problem or a redundancy?

asked by: Norman D

Expert Reply:

The additional 12-V feed called for in the # ETBC7 installation serves a different purpose than the feed for the 4-pole connector/taillight converter.

The 12-V feed for the 4-pole trailer connector/taillight converter (like # 118480) is what actually provides power to the trailer taillights. The connection at the vehicle's taillight wiring harness only triggers the trailer taillight activation, this connection doesn't supply any voltage to power the taillights. The 12-V feed for the 7-way trailer connector provided by the # ETBC7 serves a different purpose. This power source is typically used to maintain (not charge) a trailer mounted battery, powered tongue jack or minimal interior lighting.

Trying to use the same feed for both purposes is theoretically possible, but not recommended as the 12 gauge wire provided with your tailgate converter doesn't have the capacity to preform both functions. If you do not need the 12-V feed to the 7-way for any power needs on the trailer, you can certainly omit that connection. If your camper has an on-board battery that you'd like to keep maintained as you travel, you will need to run that additional feed through the 12 gauge wire provided with the # ETBC7 kit.

Running two power feeds to the vehicle battery won't cause any issues, but I'd recommend installing a battery isolation solenoid like # PK5231201 on the feed for the 7-way. The isolator solenoid disconnects power to that feed when the vehicle's ignition is switched off so the battery doesn't get discharged.