Why Wouldn't Taillight Functions of 4-Way to 7-Way Adapter Work

Updated 05/01/2025 | Published 04/20/2025

Question:

2021 Rav 4 Prime 7 pin is working with the curtains echo wirelesss break controller both the brake controller and it’s charging the trailer battery. But nothing with the 4 pin adapter is working. No lights, left, right, brake are working!!

asked by: Mike

Expert Reply:

Hey Mike, if you are using the Buyers Products 7-Way to 4-Way adapter part # 337TC1474P and none of the trailer lighting circuits are functioning then the issue is related to the 4-way portion of the adapter. I would try pulling the 4-way off and cleaning the pins of both 4-ways and then cleaning them with sandpaper. But if that's is not the fix the issue is related to how the 4-way is powered on the vehicle and you'd need to look at how it installs and fix/address as needed. It could be as simple as a fuse on the power wire of the converter.

expert reply by: Jameson C