How to Rewire Vintage Trailer with 7-Way Connector and Parts Needed  

Question:

Expert Reply:

Most of us aren't electricians, but that doesn't mean wiring a trailer is beyond us. It will take a little bit of time, but I wouldn't consider it a difficult DIY project by any means. So, to wire your 1977 Serro Scotty vintage camper, I recommend using the following parts:

- etrailer Trailer Wiring Junction Box - 7 Terminal Kit with cord # e99011
- Aero Pro LED Trailer Light Kit # TLL36RK - includes passenger and driver side tail lights (driver side has integrated license plate light), amber clearance lights, license plate mounting bracket, 25 foot 4-Pole harness and stainless steel hardware.
- Thinline LED Clearance and Side Marker Red Lens # MCL-91RK

The minimum suggested wire size for a 7-way trailer plug is 16 gauge for the turn signals, brake lights, reverse lights, and running light wires, which is what you'll get with the trailer light kit harness. The 25 foot length will more than enough to run the wires from the junction box to trailer lights, so you'll basically cut off the 4-pole connector, wire it to the junction box, run it to the lights, and cut of the excess. For all the connections, I recommend using heat shrink connectors, like # DW05744-5.

To keep your electrical connections secure and free of moisture, I recommend using Liquid Electrical Tape, # SWC50122, along with some wire loom # 39035 - sold in 10 ft sections.

For your clearance/marker lights, you want to splice into the running light circuit on your trailer. You can run them in parallel basically daisy chaining the power wire and grounding the negative wire on each light to your frame. I recommend using wire # 16-1-1 to wire these clearance lights using the same heat shrink connectors mentioned above. I've attached wiring diagram below for a typical 7-way trailer connector. And at the bottom of the page, you'll find links to step by step instructions plus additional information/diagrams on wiring your trailer in the form of help articles and installation videos.

If you plan on installing electric brakes on the trailer, just let me know so I can make additional recommendations for the parts you'll need.

expert reply by: Carla M

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Ken R.

4/15/2020

Thank you for the help and guidance. As far as brakes the trailer has brakes but the vehicle does not have those mechanicals. What would I need if I wanted to go that route? It’s a 2011 grand Cherokee with both a 4 and a 7. Just no trailer braking equipment.

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Carla M.

4/15/2020

It sound like all you need then is a trailer brake controller, for which I highly recommend the Tekonsha Prodigy P2 # 90885. It's a customer favorite because it's easy to use, it's super reliable, and it just works really well - activating your camper's brakes at the same time and with the same intensity that you apply to them in your Jeep. If the 4 and 7-Way connector on your 2011 Jeep Grand Cherokee is factory installed, you'll want to use part # TK93VR to connect directly into the brake controller port under your dash, for a plug and play installation. Otherwise, the P2 will need to be hardwired, as per the installation instructions with the included universal pigtail.

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