Trailer Connector for Towing Surge Coupler Equipped Trailer With 2013 Toyota Tundra
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Question:
I have a 2013 Toyota Tundra se work truck, with just a 4 way plug inside the bumper on the drivers side. I bought a pontoon boat with trailer with dual disk brakes. What class hitch do I need, and how do I wire this up so the trailer brakes work? Thanks
asked by: Mark L
Helpful Expert Reply:
I'll begin with the assumption that your new pontoon trailer has hydraulic surge brakes. This type of braking system uses a hydraulic coupler that compresses when the tow vehicle brakes, and the compression is what causes the brakes to actuate. A trailer like this usually uses a 5 pole flat trailer connector, with the extra circuit being the reverse lock out. The reverse lock utilizes a solenoid that prevents the brakes from applying with you attempt to back the trailer. Otherwise, especially if you're backing up an incline, the trailer brakes could apply making backing the trailer difficult.
You could of course use the # 20036 adapter you've looked at, and simply tap the extra blue wire into the reverse lamp circuit but unless you'll only be towing the trailer a few times I'd personally rather go with a more permanent solution that didn't involve an adapter.
I'd recommend simply cutting off the existing 4 pole, and splicing in a # HM37908 five pole harness. The harness would connect to your existing wiring color for color, and you'd just tap the blue wire into the reverse lamp circuit as described above. At the connection points, I'd recommend soldering the connections and using heat shrink tubing, like # DW05451 to seal the connections.
If you don't have a soldering iron, we offer one as part # PTW2012 or a battery powered cordless model as part # PTW2000. If you don't solder, heat shrink butt connectors, part # DW05744-10 would be an okay option.
For a hitch, the Curt Class V, part # C15398 is what I'd recommend. The hitch has more capacity than you need, but it's more reasonably priced than the next lowest rated hitch. You don't mention the weight of the pontoon and trailer, but if it's 6000 lbs or less, a Class III like # 75527 would work just fine for you, and would be my recommendation.
I've linked you to installation videos for the hitches I recommended.

Product Page this Question was Asked From
Tow Ready 4 Pole to 5 Pole Trailer Wiring Adapter
- Trailer Wiring
- Wiring Adapters
- Single-Function Adapter
- 0 - 5 Feet Long
- 4 Flat
- Plug and Lead
- 5 Flat
- Tow Ready
more information >
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Mark L.
4/9/2020
Hi Mike,Would this type of wiring work on my 2013 Tundra? Hopkins Endurance Multi-Tow 4-Way Flat to 7-Way RV Trailer Adapter w/ 4-Way Vehicle End PlugItem # HM47180.Im looking for a plug that can bolt onto the bumper. Thanks again