Should Blue Wire From Brake Controller Have Constant Power

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Question:

I am hoping you can help. Should the blue wire from the back of the controller have constant power?

asked by: Daniel

0

Expert Reply:

The blue wire coming from the back of your Tekonsha Voyager Brake Controller # 39510 is for brake output to the 7-Way connector. This wire should only have power with the brake pedal depressed or the manual override activated on the brake controller. If you are getting constant power on this blue wire this may be an indication that the controller is bad but there is an easy way to test this.

You will want to first sever the blue wire several inches from the back of the controller. Then use a circuit tester like # PTW2993 to test the end of the blue wire coming out of the controller. This should only have power when you apply the manual override. If you are still getting power there at idle, then there is an internal issue on the controller and it will need to be replaced.

If a replacement is in order, I highly recommend the Tekonsha Prodigy P2 # 90885. This is a great proportional controller that features continuous diagnostics to alert you to any potential issues and comes with a limited lifetime warranty.

If it tests normal (only showing power with the manual override) then go ahead and reconnect the blue wire. You will then want to move back to the 7-Way connector on your vehicle. Inspect the connector for any dirt or corrosion that might be built-up around and behind the pins. This can cause a short that might be bleeding over into the brake output pin. Clean the connector out as needed.

Then test the brake output pin on the 7-Way (5 o'clock position) to make sure it is only getting power with the manual override on the brake controller activated. If it shows power at any other time, then the issue is somewhere between the brake controller and the 7-Way. If this is the case, you will just need to inspect the wiring along the vehicle for any damaged or exposed sections, fixing/replacing as needed.

expert reply by: Chris R

0

Nick M.

7/15/2020

The test you describe above... is it implied that the trailer is plugged into the back of the tow vehicle? Is it true that the blue wire would test differently with the trailer plugged in or not? Thanks,

Reply

Chris R.

7/20/2020

If you slide the manual override on the brake controller, it should send back full power on that blue brake output wire regardless of whether or not a trailer is attached. So you can perform this test without hooking up the trailer.

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Answer 1

The only time there should be power on the blue wire when testing it should be when you are applying the manual override. If it shows power at any other time that indicates a problem inside the controller and it will need to be replaced. Also make…

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Answer 2

Based on what you have said here the brake controller is faulty and it will need to be replaced. There should not be power output on the blue wire behind the controller all the time. This indicates a problem with the internal circuitry of the brake…

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Answer 3

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 4

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Answer 5

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Answer 6

If you are reading a constant 12 volts on the blue brake output wire with the Curt Venturer Brake Controller #C74VV installed, this is indeed an indication that either the controller itself is bad or there's a short somewhere along the brake…

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Answer 7

The only wires that could be hot all the time on a trailer connector is the 12-volt hot lead, which is usually a black wire, and, if applicable, the auxiliary power wire, which is normally yellow or purple. The blue wire is usually for electric…

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Answer 8

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 9

If the Roadmaster InvisiBrake Supplemental Braking System #RM-8700 brake signal alert was functioning correctly until just recently then the issue is most likely going to be some sort of wiring damage/wear. The ground would be a great place to start…

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Answer 10

I have attached a photo for you below which shows how both a vehicle side and trailer side trailer connector is typically wired. I say typically because this is not always exact and so long as the trailer and vehicle side both match it will not…

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Answer 11

That is correct. If your 2021 Wrangler Unlimited has the connector located under the dash to the left of the steering column near the top of the e-brake pedal as shown in the provided photo, you'd use the #3073-P harness to connect the #90195…

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Answer 12

To add a 7 way to your 2022 Jeep Wrangler, you'll first want to wire in a 4 pole connector with #118786. This easy to install wiring harness plugs directly into your factory wiring for a simple installation. Following the 4 way installation, we…

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Should Blue Wire From Brake Controller Have Constant Power

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