We have an American Tow Dolly they mount the brake controller on the dolly tongue in a plastic box wired to the brake light wire of 4 pin flat plug. Once adjusted I put tape over adjustment wheel it is also run through on/off switch. When pulling dolly empty turn switch off still have lights but no brakes. I really like this setup because I can tow behind any vehicle with 4 pin flat plug don't need brake controller.
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