Blue Wire Showing Voltage with No Trailer Connected and When Not Applying Brakes on Brake Controller

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Question:

My brake controller light does not illuminate when I have the brake controller installed with confirmed + voltage to the black wire and confirmed ground to the white wire. Should that light be red if the trailer is not hooked up? Also, the blue wire is showing positive voltage without the brake pedal being depressed. When I test that wire for voltage, the light on the controller lights up green, indicating that the trailer is hooked up even though it isnt. Should that blue wire have constant voltage the #2 pin also has constant voltage at the tow vehicles 7-pin connector? Should the red light be on if there is no trailer hooked up and power supplied to the controller? Not sure what this part #5100 is. I have a Voyager Tokensha brake controller

asked by: Bradley W

0

Expert Reply:

It does sound like there is a short to the brake controller through the wiring or in the internal circuitry of the brake controller. Since your brake controller shows no red light this indicates a short to the brake line (blue wire).

If you are using wiring harness, # 3040-P, make sure that extra white ground wire is attached to a clean bare metal surface. If it is hardwired to the truck, the ground needs to be connected to the negative battery terminal.

Sever the blue wire a few inches back from the controller and use your circuit tester to test the wire. If it shows voltage without applying the manual override, then this indicates a problem inside the controller and it will need to be replaced. If the issue stops, there is a wiring problem somewhere between the controller and 7-Way.

The controller will send a small amount of power back to check to see if a trailer is connected but it should be just a tiny amount. Applying a circuit tester to the wire could trick it into thinking there is a trailer connected because it adds more of a load on the system.

You would need to check to make sure the wiring is intact on the harness and on your truck including the grounds. If you cannot find a wiring or ground issue, then something is wrong with the internal components of the brake controller and it will need to be replaced as there are no internal serviceable parts.

expert reply by: Michael H

0

Answer 1

On the 2009 Chevy Silverado there is no port to plug in a brake controller. Instead GM put a tow package wire bundle under the dash. You would use the harness with the blunt cut wires that comes with the brake controller and splice into the tow…

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Answer 2

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…

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Answer 3

If the blue output wire is showing power when it should not be then that indicates that the controller is bad and will need to be replaced. But to test it properly you will need to sever the blue wire a few inches from the back of the controller.…

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Answer 4

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…

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Answer 5

All the brake controller needs to sense a trailer connection so that you can test it is a slight amperage draw on the output circuit. For that you can use a circuit tester like the part #PTW2993 with one pin grounded and the other on the output pin.…

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Answer 6

I have a suspicion about what might be causing the problem you mention. Do your trucks have 6-way trailer connectors? Or, do the trucks have 7-way connectors, but you are using a 6-way to 7-way adapters because the trailers use 6-way connectors?…

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Answer 7

There could be in internal short in the brake controller. Use a circuit tester like part #PTW2993 on the blue wire exiting the rear of the controller. There should be no voltage on that wire unless the brake pedal is pressed, or the manual brake…

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Answer 8

The controller is only putting out voltage when the manual switch is applied on the brake controller, but not when the vehicle brakes are applied, is that correct? The most likely problem is that the controller is not getting the input that the…

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Answer 9

You are correct, you should only be getting output when the brake is applied, or the override switch is activated. It sounds like the controller might be bad, but to make sure, you should probably bench test it before tossing it. Use a circuit…

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Answer 10

You will have no problem using a Dexter brake assembly on a Lippert 7K axle. We have installed several Dexter brake assemblies on Lippert axles at our shop. Lippert and Dexter use the same standard mounting pattern and brake sizes. If you want…

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Answer 11

Actually, there's a little more to it than that. The magnets on the #K23-478-479 are a little different, but the primary difference is the mounting bolt pattern. On a typical 3500 lb brake assembly, the mounting studs will all be 2-7/8 inches…

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Answer 12

No you should not have constant power on the brake output pin, the blue wire should only have power with the brake pedal depressed in the vehicle or the brake controller manual override is activated. If the blue wire has a constant 12V then it is an…

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Blue Wire Showing Voltage with No Trailer Connected and When Not Applying Brakes on Brake Controller

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