Does Connection of 4-Pole Harness to Adapter C57674 Include Additional Trailer Circuits

Question:

INSTALLING C57674 WIRING HARNESS ON A 2013 TOYOTA FJ. MY FJ COMES WITH A 4 WIRE HARNESS. TO INSTALL YOUR ABOVE UNIT IS IT ONLY PLUGGING YOUR THE FOUR WAY TOO MY FOUR WAY AND NOT THE OTHER FOUR LOOSE WIRES. YES OR NO?

asked by: DEWILDA

Expert Reply:

Curt Adapter # C57674 is designed to plug in to an existing functional 4-pole wiring harness to convert the 4-pole's lighting signals into the 7-way connector format. Plugging in the 4-pole from your vehicle will allow those same stop/turn/tail lighting signals to pass through to the electrical contacts in the 7-way to allow a trailer with a 7-way plug to receive them. If you refer to the linked photo of a 7-way socket you can see the usual arrangement of functions.

The pigtail leads on the adapter allow connection of additional circuit wiring to support the additional functions included on a 7-way. These additional functions are +12V power for a trailer, reverse lights and trailer brakes. Those additional circuits/functions will be active ONLY if you make those additional connections. If not, you will still have all the same lighting signals from the flat 4-pole connector, only in the other connector format.

If your goal is to have a fully-functional 7-way with all circuits active then a better option is to use our # ETBC7 kit which includes an adapter like the Curt, but which also includes all of the wiring and other parts needed to have a fully-functioning 7-way.

expert reply by: Adam R