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Curt Wiring - Wiring Adapters - C57672 Review

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Review of Curt Wiring C57672

Today we're taking a look at the Curt 4-pole to 7- and 4-pole adapter. Now this unit adapts a standard 4-way flat connector on your vehicle, to both a 7-way RV, and a 4-way flat connector. So this gives you the convenience of having both connector styles available at the back of your vehicle when you tow a trailer. This is really handy if you're towing different trailers, like you're towing maybe a trailer that just uses a 4-way and then you're switching over to towing a trailer that has a 7-way. This is really nice because now you have both options available at the back of your vehicle.I do want to point out that each connector has a really nice cover that goes over, and keeps the connector clean when they're not in use. And right here's your 4-way.

And then right here is your 7-way. That's a spring loaded lid. Internally, it's got like a rubber gaskets and that creates a nice tight seal when it's not in used. Or excuse me, when it's not in use, and keeps dirt, grime and moisture away from those connection points. The wiring on the back, this is a split loom design, keeps the wires contained and well protected.

And it also comes with hardware, and a metal mounting bracket to secure the wiring connectors to the vehicle or directly to the trailer hitch. Now, your installation is pretty straightforward. This 4-way right, here connects to the 4-way on your vehicle. And then you have four more wires that you need to connect. And then really you're done.Already on the end of each wire is the appropriate connector.

So on these three we have butt connectors. Yellow wire is for auxiliary or backup lights, blue wire is for electric brakes, black wire's for positive power, and then the white wire with the ring terminal on it, that's your ground wire. And that's going to do it for today's look at the Curt 4-pole to 7- and 4-pole adapter.

Questions and Comments about this Video

Thats great but how do you connect eh backup, brakes and positive power to the vehicle. I have installed your four pole flat but now I need electric brakes
Etrailer Expert
Reply from Rachael H.

If you have not already purchased this item i recommend getting a complete install kit # ETBC7 , of which this wiring harness is a main component of the kit. IF you do have this part and the 4-way only, then to install a fully functional 7-way you will need other components that I have provided links to below to complete the installation.I have included a link to another kit that will have most of the parts that you will need # 5506 , individual pieces and hardware that you may need to route the wires for a 7-way. The reverse wire on the # C57672 harness (purple) will tap into the reverse light circuit (backup) wire on your vehicle, you will need to test for function to find this, using a tester like # ALL640595 The brake signal will be routed from the brake controller (in cab signal) to the back of the vehicle at the 7-way location. The 12V (positive power) will be supplied by the vehicle battery, and needs to use an in-line circuit protector (supplied with part # 5506 ). I also included a link one of our help articles that explains the step by step process needed to install the ETBC7 as well as video showing the entire installation process. If you don't already have a trailer brake controller you will need one of those too to detect the brake signal from the vehicle and send it to the 7-way.

Info for this part was:

Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video by:
Dustin K
Employee Thomas T
Video by:
Thomas T
Employee Cole B
Installed by:
Cole B
Employee Conner L
Test Fit:
Conner L
Employee Bradley B
Test Fit:
Bradley B

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