Troubleshooting Trailer Running Lights Staying On when Vehicle is Turned Off

Question

Question:

my trailer parking lights stay on when the vehicle switch is off

asked by: david p

0

Expert Reply:

It sounds as though there is a short or something is mis-wired. Using a circuit tester, like the # PTW2993, check the connection points in the vehicle side connector, to see if there is constant power on the running light circuit (brown wire on the 4-Way) when the vehicle and lights are turned off.

There should be no signal when the lights are off, and a signal when they are on. If there is a signal with the lights off, then there is a problem on the vehicle side. Check to make sure that the brown wire is properly connected to the running light wire at the rear of the vehicle and that the white ground wire is attached to a bare metal surface that is free of dirt and corrosion. It could also be a bad converter.

To test a converter, you will need to first test the wiring going in for function. If the functions are incorrect going in, then something is mis-wired and you will need to start again as if installing the unit for the first time. I have included a link to the installation details for the # C59496 below for reference. Depending on the vehicle, you may need to pay special attention to the directions regarding 2 wire and 3 wire systems and install according to the wiring on your vehicle.

If the functions are correct going in to the converter but incorrect going out, then there is a problem inside the converter and it will need to be replaced. If the signals are correct going in and coming out, the issue lies elsewhere. I have included a video below, on testing a converter, that should help.

If there is no signal with the lights off, then the issue is on the trailer side. If your trailer has a separate battery, make sure it is not connected to the tail light wiring. Also check to make sure all of the grounds are secure and attached to bare metal surfaces free of dirt and corrosion.

You should also check all of the ground connection points on the trailer to be sure the power is not back feeding through the ground when the vehicle is turned off and the trailer is connected. The power from the 12 volt connection could be looking for a ground and is finding the connection through the taillights. Check the taillight connections to the trailer and the ground at the trailer coupler to be sure they are connected to good clean trailer frame grounds.

expert reply by: Michael H

0

Answer 1

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Answer 2

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Answer 3

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Answer 4

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Answer 5

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Answer 6

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Answer 7

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Answer 8

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Answer 9

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Answer 10

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Answer 11

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Answer 12

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