What brake controller are you using? Some Need to see tow vehicle movement.
A simple test we use is to pull the pin on the break away. If the brakes are tight enough, you should be able to torque the lug nuts to 120 lb/ft.
2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.