Electric Trailer Brakes Troubleshooting

[HappyOne]

I went out and checked everything. Good ground wired directly to the brakes from the truck. With nothing hooked up, blue shows 12v. With the trailer hooked up, voltage drops to barely measurable. With the controller manually engaged, I now see .25 volts and you can hear the brakes lightly buzz. I checked the voltage feeding the brake controller and it is fine. I hooked 12v directly to the trailer plug and the brakes lock like they should. At this point, I am fairly certain the brake controller is due for a replacement.

 

[crazyal]

It sounds like you've got it figured out.

 

[HappyOne]

I hope so. Now I need to decide if I get another Tekonsha Voyager or something a little more robust. I will be upgrading to a trailer with slightly more hauling capacity and likely want brakes on every wheel. Is there a more reliable one out there?

 

[joshuabardwell]

Prodigy by Tekonsha is widely regarded as one of the best, FWIW. At least that's my impression.

 

[Travelover]

Prodigy by Tekonsha is widely regarded as one of the best, FWIW. At least that's my impression.

The Primus, P2 and P3 controllers all have a limited lifetime warranty. They are well regarded in the recreational towing world.

Brake Controllers - Tekonsha

 

[crazyal]

It seems like 99% of trailer electrical problems are due to a poor ground. My advice is to not use the frame as a conductor. Wire is cheap, so just run a separate ground wire to each brake and light. I avoid crimp connections where water can get to them, opting for solder and shrink tape.

In short, don't just fix the current problem, fix the future problems while you are at it.

Solder is actually a poor choice for connections where there is vibration. It has no give, so it cracks eventually. Wire nuts or crimp-on connectors are the recommended way of making automotive wire connections.

I use the crimp on connectors but I'll coat the wire with NoOx first and whenever possible I try to use tin coated wire.

But my best advice is to do is weld stainless bolts to the frame near every place things like brakes, lights, and the ground from the 4/7 plug harness grounds.

This is the old zip screw factory ground and a replacement ground spot (1/4-20 bolt). Being stainless it'll never rust. Being welded to the trailer frame means it'll always have excellent conductivity. Every trailer I own gets upgraded to this style ground.

 

[crazyal]

Does the voyager have short circuit protection? I know my P2 does and would assume that all of the prodigy line does. You'll spend more than twice the money and you need to tap into one of your hydraulic brake lines but there are plenty here who swear by the MaxBrake.

 

[Travelover]

.................
But my best advice is to do is weld stainless bolts to the frame near every place things like brakes, lights, and the ground from the 4/7 plug harness grounds.
...........

Not to belabor this discussion, but why use the frame as a ground at all? It seems like running a separate ground wire solves a lot of problems that making a connection via the frame causes.

 

[aczlan]

I went out and checked everything. Good ground wired directly to the brakes from the truck. With nothing hooked up, blue shows 12v. With the trailer hooked up, voltage drops to barely measurable. With the controller manually engaged, I now see .25 volts and you can hear the brakes lightly buzz. I checked the voltage feeding the brake controller and it is fine. I hooked 12v directly to the trailer plug and the brakes lock like they should. At this point, I am fairly certain the brake controller is due for a replacement.

I would try hooking 12 volts to the truck side of the plug on the brake controller itself (ie: unplug it and apply 12v there) just to make sure it isn't something else in line there.
Your problem could also be caused by a bad wire between the controller and the plug at the back of the truck.

Aaron Z

 

[joshuabardwell]

I would try hooking 12 volts to the truck side of the plug on the brake controller itself (ie: unplug it and apply 12v there) just to make sure it isn't something else in line there.

This is excellent advice! Also, I didn't catch whether the 0.25 volts was measured at the trailer or the controller. I thought it was the trailer, but now I'm not so sure. It may be worthwhile to measure the output from the controller too. You will need to connect the controller's brake output pin to its ground pin to convince it that a trailer is present. Use a taillight as a load to prevent a dead short.