Trailer brakes won't grab

My trailer is roughly 2000#, but I can't get its electric brakes to work. I set the P3 brake controller up to 12V, and adjusted the brake magnets at the drums as close as possible, but it's stil not enough to stop the trailer. I can hear the brakes being magnetized when I hit the brake or slide the brake lever on the controller.

What else should I check?

 

Check voltage and ground at the brakes, just because you have 12v at the plug doesn't mean you have 12 at the brakes.

Trailer brakes wear just like regular brakes.

Define "stop the trailer". It shouldn't take much to stop 2k. Can you make the wheels lock up? Are you trying to stop the truck and trailer with just the trailer brakes?

 

Are you checking while in motion? The P3 has an inertia bias built in.

 

Manual lever should bypass the controller completely.

 

IRCC the P3 instruction manual states that you should increase the power setting until you're able to fully lock the brakes while towing at 25 MPH using the override lever. All trailers and brakes are different but in my experience 12 sounds like a good setting for a 2000 lb trailer. But anyway, can you lock the brakes using the over ride function? I don't know what you mean by "stop the trailer". You wont be able to stop the truck and trailer combo very well using only the trailer brakes because your truck is much heavier than the trailer.

 

Thanks all for the replies. By "stopping the trailer," I am referring to trailer wheels locking up or create enough drag to slow down the truck and trailer at a 5mph roll. I tried the 15mph brake check with the manual brake override, but that was too fast to notice anything, so I tested at much slower speed.

 

That's exactly the test I did. The max power setting on the P3 is 14, so I think 12 is way too much for a 2000# trailer. I was expecting wheels locking up at around 4 at 15mph.

 

If the drums are fine, maybe check the voltage that's getting to the brakes? Since it's newer, it seems unlikely that your truck's system is faulty. Maybe the trailer isn't wired correctly?

 

While braking with the P3 it will display the current voltage applied. This is determined by the settings and the inertia. When I apply the brakes softly at low speeds it barely applies the trailer brakes at all.

If while manually applying the brakes you still get nothing I would pull your trailer with another vehicle and test the brakes with their controller to verify if the problem is with the trailer. If it is good then you know you have an issue with your truck / controller and it’s system.

 

Remove all scotch locks from the brake wiring if present and replace them with butt connectors.

 

Both my trailers did the same thing with my 08 Tacoma. I found that the ground wire at the trucks plug-in starts as a 10 awg and goes to a much smaller wire about 10" from the plug-in and grounds to the top of frame at the drives rear wheel. I sliced a 10 awg wire to the 10 awg truck wire and grounded it to the hitch, my trailer brakes work great now.