Trailer Brakes Not Working When Using Hopkins Engager Trailer BreakAway Kit # 20099

Question:

We have voltage but weak on a test light what is the voltage required to fully activate the brakes. Can this be a common ground issue.

asked by: Ron

Expert Reply:

The Hopkins Engager Trailer Breakaway Kit, part # 20099, uses the 12V power wire on your vehicle 7-way connector to charge the breakaway battery so it can activate your trailer electric brakes in the event of a trailer disconnect. Your tow vehicle battery provides the charging voltage for the breakaway battery (but only when the engine is running).

I suggest you review the linked article concerning the installation of breakaway kits. This covers important details for both installation and operation. I have also included the manufacturer instructions for this part and a second article on testing breakaway systems. A general installation video is also provided for reference.

If you know your trailer brakes are fully operational and you are finding they will not activate when testing the breakaway kit, first verify that the tow vehicle battery is in good condition and fully charged. Next inspect the wire carrying the 12V power to the 7-way for signs of worn or cracked insulation. Check the pin at your vehicle 7-way connector (the pin at the 1-o-clock position - see photo provided) for any signs of corrosion. Even a very slight greenish or whitish discoloration of the contacts could inhibit power transmission to the trailer and result in an insufficient charge to the breakaway battery. Also check that the white ground wires, on both the vehicle and trailer sides of the 7-way, are solidly attached to clean, rust-free unpainted surfaces on the vehicle and trailer frames. Last inspect the 12V wire from the trailer connector back to the breakaway kit; again look for worn spots or cracks in the insulation and confirm that the physical connection at the 7-way is clean and secure.

Hopkins indicates a 20 minute charging time for the breakaway battery while the vehicle is in use. The charging light on the breakaway kit will always stay on as long as the trailer is connected to the tow vehicle, but that does not mean the battery is charging. The vehicle must be running in order to charge the breakaway battery.

Last you can test your trailer electric brakes for proper function by following the steps outlined in the linked article. This includes a reference table for the correct current readings you should find depending on the size of your drum brakes.

expert reply by: Adam R