Draw-Tite Activator Brake Controller Shows an Overload OL Condition When Trailer is Connected

Question:

on my 1989 chevy truck my brake controller works 3.5 but when i plug up da pig from my trailer i get da core OL i checked da ground and its ok.can you guys help me? thanks

asked by: Dexter L

Expert Reply:

The OL on the display for the Draw-Tite Activator, # 5100, indicates an overload condition. This can be indicative of a short circuit along the blue wire of the brake controller. The short could be the result of a bad ground, broken wire, corrosion in the trailer connectors, or any combination of these.

Start by checking the wiring at the back of the brake controller to ensure that the ground is connected to a clean bare metal surface if it was hardwired. You can use a circuit tester like # 3808 if needed to test the voltage on the blue wire to see if the controller is sending back the correct voltage at the right times (when the brake is pressed or manual override engaged). If it does not, there could be a problem with the internal circuitry of the brake controller and it will need to be replaced.

Next you can check the ground at the truck side 7-Way. It will need to be attached to a clean bare metal surface on the frame. Also look inside the connector and at the back where the wires attach for dirt and corrosion and clean out any you find.

You can then move on to the trailer by checking the connector for dirt and corrosion, and checking that the main ground is intact. If you test the vehicle side connector with the circuit tester without the trailer attached and the brake controller is working fine, then you know the issue is on the trailer side.

You can then move on to testing the brake magnets. Start with a visual inspection of the magnets. If you can see the windings coming through, the magnets will need to be replaced. Also check that the power wires to the magnets and the ground are all intact and attached like they should be with no breaks, nicks, or corrosion.

After visually inspecting the magnets, you can perform further testing using a separate 12 volt battery and a multimeter like # BTMT15. I have included a link to an FAQ article on how to test brake magnets. I have also included a link to a video on troubleshooting a brake controller.

expert reply by: Michael H