Troubleshooting Hopkins Trailer Brake Controller That Does Not Show Connection to Vehicle
Question:
So hooked it all up. Quick connect for a 2011 tundra. Super easy. States within paperwork I should have a red dot on lower right corner when trailer is hooked up. Trailer is hooked up, lights on trailer working fine as usual. I can manually press slide to brake or at least the digital read out is working. I’m assuming even though my trailer is hooked up and I don’t have a dot then it’s not recognizing my trailer and thus not going to engage my trailer breaks? I’m wondering is it a wiring issue back by tow package? I checked wiring diagrams and where the electric brake is located on the 7 blade. Should be working but not. Please help. Thank you
asked by: Troy
Expert Reply:
If applying the manual over-ride lever on your Hopkins trailer brake controller, such as the Agility # HM47295, sends brake power back to your Tundra's 7-way then you know the circuit is functioning. You can test by having a helper press the lever (with the controller set to maximum output) while you apply a circuit tester like # PTW2993 to the trailer brake circuit's pin, the one at the 5:00 position as you view the vehicle socket. Please see the linked photo.
If your test indicates brake power reaching the 7-way, then the connection issue (and the reason why you do not see the dot on the display) is likely to be a short or other problem on the trailer. If there is a short in the brake circuit wiring or bad magnets on the trailer that would prevent the controller from properly detecting the connection. I linked an article on testing magnets.
You can also independently test the trailer brakes without the vehicle or controller involved simply by directly applying 12V power (from the vehicle battery or from a well-charged spare) to the appropriate contacts on the trailer plug. Please see the other photo I linked for you.
You can also refer to the two linked articles for additional troubleshooting help.

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