A good guideline is that a trailer must have brakes if the GVWR is above 3,000 lbs. However, laws pertaining to trailer brakes vary by state and province, and some laws require brakes below 3,000 lbs. Consult your local Motor Vehicle Department to determine the requirements for your region. It is a universal rule that any trailer used for commercial purposes must have brakes on all axles.

Refer to the axle manufacturer’s manual for troubleshooting guides.  Click product support for manuals.

Voltage can be measured at each wheel to determine if there is ample current.

The newest technology in drum style brakes is self-adjusting.  Older model drum-style brakes need to be adjusted semi-annually at minimum and more often in high-use applications. Surge disc brakes do not need adjustments.

Testing can be done by pulling the breakaway cable which will activate the brakes via the small battery usually located near the front of the trailer. This will test not only the service brakes but also the emergency brakes. To test the service brakes only, slide the thumb switch fully which should apply full brakes to each applicable wheel with brakes; test while driving slowly in a vacant parking lot.

Electric brakes are activated by a magnet in the brake drum. The magnet is energized by an electronic brake controller in the tow vehicle. Newer tow vehicles typically have the brake controller installed in the dash, however aftermarket controllers are readily available. If you are inquiring as to which magnet wire is positive and negative, the wires are interchangeable on the brake magnets and can be wired in either direction.