Brake Controller Troubleshooting

You can find out a lot about your electric trailer brakes and wiring without even pulling a wheel off. Of course, you’ll still want to do that at least once a year to check the condition of your brakes and wheel bearings. But here’s a quick guide to ensure your brakes are ready for your next trip.

The Compass Check

Have a helper hold in the manual stop button on your brake controller while you hold a magnetic compass within 6” of each wheel. If the magnets are working, the compass needle should swing toward the wheel.

The Heat Check

This is a little more involved and requires a laser temperature sensor (But they’re really cool, you can use it in your kitchen, too!) Take a short trip around the block, braking as often as safety allows. Hop out and use your laser sensor on each wheel. Each wheel should be well over the air temperature and, hopefully, nearly the same. If one is much colder than the rest, you have a problem with that brake. They should be within 70 degrees Fahrenheit of each other.

The Amperage Check

By far the best method. This requires a brake controller that gives you an amperage reading. Keep in mind that, in most models, the amperage is limited by the brake controller itself. With the TruControl™, simply push the manual stop button while parked. The vehicle does not need to be running. You should see at least 3 Amps per trailer brake. If you have 2 axles (4 brakes), you should see 12 Amps or better. 11 Amps is nothing to panic about, but is a good indication of the condition of your wiring or magnets. If you see 9 Amps, you can be reasonably certain you have one brake not functioning at all. 6 Amps means you’re down to 2 brakes, etc. Note the explanation and images to the right.

At the other end of the scale, if you see a high amperage readout, anything over 5 Amps per brake, you probably have a bare wire in contact with metal somewhere. Likely, it’s the blue trailer brake wire in the tow vehicle or trailer. The trailer wire is easiest to inspect and the most likely culprit. Start with the plug itself. Is it corroded or dirty? Then check the junction box under the frame. The cover pops right off and you can see if any connections have come loose. Follow the blue wire along the bottom of the trailer, inspected for areas where it’s rubbed off the insulation. Repair this immediately with electrical tape. Get the wire replaced as soon as possible. This will blow a fuse in the tow vehicle and pulls power from the brakes. Too understand more on how the power acts like water click here.

Recommendation

The best cure can’t beat prevention. Upgrade your system to a TruControl™, which will give you excellent diagnostic capabilities and fantastic power output. Upgrade your trailer brake wiring to heavier gauge wires and wire the brakes in parallel. This ensures equal braking power and maximum power to each brake. You can easily do this yourself or order the TruBrake™ system from Hensley, which gives you the TruControl™ and a wire harness kit. The support staff at Hensley can answer any of your questions. Call them at 800-410-6580. They’ve talked more than a few customers through an installation!

Call 800 410-6580 for Pricing...

Call 800 410-6580 for Pricing...

Troubleshooting

In a perfect world on a 4 Axle trailer utilizing 12" wheel brake magnets and a TruBrake System you may see 32 Amps, however in most cases you will not due to wire gauges and connections

In the above picture is the expected output for a 4 Axle trailer. Yes 28 Amps divided by 8 yields 3.5 Amps per magnet.

That means on a 2 Axle trailer you should see 12 to 14 Amps if all your magnets are working correctly.

Note we recommend being able to read 3 to 4 Amps per magnet. Therefore on a 2 axle trailer you should be able to read 12 to 16 Amps on your brake controller. If your in the 10 Amp range and your using the TruControl then you should consider getting the TruBrake™ wire harness kit.