Trailer Brake Controller is Putting Out Low Voltage when Set High on a Dump Truck

Question

Question:

I have a 2000 hino fb cab over dump truck, i have 13.8 volts going into the controller, when the manual lever is applied i only get 11 volts out.on the blue wire . i replaced this controller with another brand new one and see the same results. Im measuring 9 volts at the magnets....i see 11 volts at the trailer plug at the back of the truck. as soon as i connect the trailer and apply manual lever it s to 9 at the magnets. Its a tandem axle trailer i just replaced all 4 brake assemblies

asked by: Neil

0

Expert Reply:

The longer distance the power has to travel, the more the voltage will drop. But if the controller is set to the max output then you should have nearly 12 volts at the trailer connector.

If you are testing the blue wire directly behind the controller, make sure that you sever it first because otherwise the result could be skewed. If the controller is still not showing at least 12 volts with the manual override this time then make sure the controller is not tilted or turned to the side and that the leveler, if it has one, is properly set. I have seen erratic behavior from a controller because the leveler was slightly off.

Also you will want to make sure the ground is substantial for the controller to function properly. The best place for the ground is to connect it directly to the negative battery terminal. A more substantial ground may be all you need.

You will want to check the blue wire going back to the trailer connector for any breaks and repair as needed. Also make sure that both the vehicle and trailer side connectors are clean and free of corrosion inside and out and that both are grounded to clean and corrosion free bare metal surfaces.

On the trailer side inspect the wiring to the magnets for any breaks and fix as needed. The magnet grounds should also be attached to clean and corrosion free bare metal surfaces. I have included a couple of links that should help you troubleshoot further.

expert reply by: Michael H

0

Answer 1

To determine why you do not have any power on the blue brake output wire, I recommend starting at your brake controller. First, make sure the brake controller is on and receiving power. Most brake controllers have 4 wires, blue (brake output to…

view full answer...

Answer 2

I believe you almost solved the problem when you swapped the wiring, but in reality you needed to use 10 gauge wire like part #10-1-1 (sold by the foot). You are experiencing a voltage drop due to the long distance of wire that's not thick…

view full answer...

Answer 3

There are some common things you can check to determine what is causing the poor braking performance. First, you do not want the trailer brakes to lock up and skid. You want them to be at a point just under that. The resistance of 12-1/4 inch by…

view full answer...

Answer 4

Something is obviously causing a voltage drop between the brake controller and the trailer connector. The usual culprit in this type of situation is a break in the wire or a corroded wire. Check the wiring under the truck. You should be able to trace…

view full answer...

Answer 5

If your trailer has 7 wires running all the way back to the brakes, then yes, you can tap into the existing wiring. Each of your new brakes will have two wires for the brake magnet. One wire is for 12 volt power to the brake magnets and the other…

view full answer...

Answer 6

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

view full answer...

Answer 7

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

view full answer...

Answer 8

To determine the size of the brake assemblies you need you have to measure the depth and width of the hub drum on the axle like what you see in the picture I attached. The most common size is 2-1/4 inch wide like the #T4071600-500 that you…

view full answer...

Answer 9

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

view full answer...

Answer 10

You will have to go with a sliding hitch to allow the trailer to make tight turns. For a trailer 8 feet wide the only bed length that's going to allow 90 degree turns without a slider is a stationary hitch. That being said you have two options.…

view full answer...

Answer 11

The OEM prep package consists of 4 "pucks" in the bed of the truck that will allow you to drop in puck style hitches for easy installation and removal, that gives you a completely clear bed when not in use. The B&W Companion OEM 5th…

view full answer...

Answer 12

Even though I cannot comment specifically on the grease you used because I am not familiar with it, I can tell you the best grease for trailer bearings is a a grease with a rating of GC-LB, which just means it is made to withstand very high…

view full answer...

Trailer Brake Controller is Putting Out Low Voltage when Set High on a Dump Truck

Product Page this Question was Asked From

Featured Help Information

Instructions

Miscellaneous Media

Continue Researching