How to Install a Curt Echo Wireless Brake Controller on a 2015 Lexus RX450h with Existing 4-Way
Updated 10/21/2026 | Published 10/18/2026
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Question:
I have a 2015 lexus rx450h. I have currently installed the Curt 56083 4- way. I would like to check if I use the c57674 with the c51180 and 12v line. would that be all that would be needed ?
asked by: jason m
Expert Reply:
Hey there Jason.
Yes, you're on the right track! Since you already have the Curt 4-Way Wiring # 56083 installed on your 2015 Lexus RX450h, you can use the Curt 7-Way Adapter # C57674 along with the Echo Wireless Brake Controller # C51180.
However, I'd recommend our 7-Way Upgrade Kit # ETBC7L instead of the C57674. It includes the 7-way connector, mounting hardware, wiring, and circuit breaker needed to run a protected 12V power line from your vehicle's battery. The Curt doesn't come with the wiring and connections needed so that's why our in-house kit is better.
You'll simply connect your existing 4-way, ground the new 7-way, and run the included power wire to your battery through the circuit breaker. No additional brake output wire is needed since the Echo handles the trailer braking directly at the 7-way connector.
That will give you everything you need to operate the Echo and your trailer's electric brakes. You won't need to hardwire anything into the dash like you would with a standard wired brake controller.
What kind of trailer are you planning to tow?
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Product Page this Question was Asked From
Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps
- Custom Fit Vehicle Wiring
- Wiring Adapters
- Universal Fit
- 4 Flat to 4 Flat
- 4 Flat to 7 Blade
- Plug and Lead
- CURT
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Ed L.
10/20/2026
i installed the trailer plug with the test lights and the trailer led sends a false load telling my brake controller that the trailer is plugged in when its not, So if its plugged in and the trailer plug comes out the brake controller thinks the trailer is hooked up. Kind of dangerous really. You really don't need a trailer led test light, I'm thinking of breaking the led bulb out of the socket.