Wiring Exterior Trailer Lights to be Powered by Reverse Circuit and On Board Battery

Updated 07/30/2018 | Published 07/28/2018

Products Featured in This Question

CTEK MULTI US 7002 12-Volt Universal Battery Charger w/ Pulse Maintenance and Backup Power

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In-Line Circuit Breaker - 20 Amp - Perpendicular Mount Bracket

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$6.52

Pollak Universal-Design Rocker Switch - SPST - On-Off - 12 Volt - 20 Amp - Black

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$11.77

Roadmaster Hy-Power Diode - (Qty 1)

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$22.30

Question:

All, I want to add an on board battery to power both the trailers original equipment interior lights when disconnected from tow vehicle and to power some exterior LED spots I just added. I already ran a new 14 ga. wire from the center pin on my 7-pin so the exterior spots act as hi-mount back-up lights. I would like to be able to separately switch them so they can operate off the on board battery too. I bought the CTEK 3300 from you already and plan to hook that up also for shore power recharging. I also ran a new 10 ga line from the empty aux power pin on my 7 way to a battery box. I bought an isolator from you too that I will install in the tow vehicle so I can charge the trailer battery while underway. I want to keep the original switches for the original interior lights too - just be able to power from battery on board or harness power. I keep confusing my self with switching and could use a diagram that tells me where to run which switch to where and where I need fuses. Does any of that make sense? Can you help me out with a simple diagram please? Its a 2010 Dodge Ram 1500 and a 6x10 American Hauler enclosed, no brakes. Thanks in advance.

asked by: Bruce B

Helpful Expert Reply:

In order to wire your exterior hi-mount trailer lights so that they are powered by the reverse light circuit on your Ram but can also be powered by the on board battery, you will just need to use a diode like the Roadmaster # RM-790. The output side of the diode will go to your exterior LED lights, while the input side will go to the center pin on your 7-Way and also to your on board battery via a switch like # PK34308. I also recommend adding a circuit breaker like # 9506P before the battery.

Your interior lights can just be wired directly to the battery to be used with your existing switch. You can add a circuit breaker to this connection as well.

I have attached a diagram to assist.

expert reply by: Chris R