Should the Blue Trailer Connector Wire be Hot All the Time

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Question:

Is the blue auxiliary wire to trailer hot all the time?

asked by: Lonnie

0

Expert Reply:

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 trailer brakes and if it is hot all the time that would indicate a short.

I have included a link to our help article on trailer wiring that has numerous diagrams showing the functions of the pins for many trailer connector styles. You can't always go by color though, so it is recommended to test connectors using a circuit tester such as # PTW2993, or a meter if you have one, to verify functions.

expert reply by: Michael H

0

Answer 1

The blue brake wire should not always be hot; what that means is you likely have a short somewhere that you will need to find. To do this and look for wires that may be pinched or otherwise damaged and fix as necessary or replace it with 10 gauge…

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Answer 2

The 12V wire at the vehicle-end trailer connector being hot even when the truck is off can vary depending on the application. For all aftermarket hardwiring installations of a 7-Way wiring harness, the 12V wire will be hot at all times, even when…

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Answer 3

You may have a short to the blue brake controller wire or pin on the 7-Way. This can occur from several sources. To check the brake controller, cut the blue wire several inches away from the controller. Use a circuit tester like #PTW2993 if needed to…

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Answer 4

The #HM42190 is a replacement wiring harness for a Wrangler Unlimited that's already equipped with a 7-way. If you don't have the OEM 7-way, the connector won't be present. To convert your existing 4-pole to t a 7-way, use the #37185…

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Answer 5

The light that indicates that the 12 volt circuit is hot is normal and it will not drain the battery. Think of it as the battery having a really long positive terminal that just extends to the rear of the vehicle. If nothing is drawing power from it,…

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Answer 6

Since you had the Curt Venturer Trailer Brake Controller part #C74VV installed and working on your 2015 Ford F-250, the problem is more than likely on the 2000 Ford F-350 and not on the controller. Your 2000 Ford F-350 could have come with either a…

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Answer 7

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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Answer 8

You can use a circuit tester like #PTW2993 to test the 12-volt circuit on the 7-Way to see if it is has power. If it is not and the 7-Way is factory it might just be a blown fuse to that circuit. Use the owner's manual to find the location of the…

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Answer 9

The only pin that should be continuously showing 12V power on the 7-Way connector on your vehicle is the 12V power circuit which is normally the black wire but not always. In 7-way wiring the 12V auxiliary power feed is carried on the contact at the…

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Answer 10

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 11

How old is the brake controller? Does it still seem to be working properly? Overheating brake controllers aren't common but it would most likely indicate a short. I can help you troubleshoot the controller though. Testing the brake controller is…

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Answer 12

It does sound like there is a short on your trailer. If the brakes locked up and the brake controller unit got very warm it sounds like there is a short on the trailer's 12V power circuit that is causing the electric brakes to lock up. It is…

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Should the Blue Trailer Connector Wire be Hot All the Time

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