Trailer towing used to be simple and straightforward. You’d get a hitch and a simple four-pin trailer wiring kit installed, hook things up, and head out to the cottage or storage unit — and then look for some back pain medication after your moving chores are finished. But more trailers now come pre-wired for a seven-pin hook-up, servicing additional circuits for electric trailer-brakes and/or reverse lights. And for those vehicles that come with trailer tow packages from the factory, more and more of these are being equipped with both four- and seven-pin setups.

The biggest drawback with a seven-pin system is that, if you don’t have a trailer-brake controller mounted on the dash, you’re not getting the full benefit of the trailer’s braking system. Having the ability to adjust the amount of braking force — via a controller — allows the driver to match the trailer’s braking performance to the load being placed on it.

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