Troubleshooting 2003 Toyota Tundra Trailer Brake Light Always On Hot
Published 11/16/2017
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Question:
I forgot to tell you that the lights are on even if the truck is off. No other lights of any kind are on. The running lights on the truck are not on. Two places have said it is factory. So in other words. I would have to unplug the trailer evertime I’m not driving.
asked by: Brooks
Expert Reply:
The prong next to the ground on a 4-way flat is for trailer running lights. It should give you a light anytime your vehicle is running for trailer running/parking lights. If it is activating your brake light, then there most likely is a wiring issue and that can be on your vehicle or your trailer. Since there is not a factory 4-way available for your truck model year, we know there isn't a relay issue.
The brown wire is your running/park/tail lights. The yellow wire is the left side brake and turn signal. The green wire is your brake and right turn signal. The white is your ground wire.
You can test these functions using a circuit tester like # PTW2993. If you determine the issue is on your vehicle side, it is very likely that you have an improper splicing or a bad converter box. You can use the 4 Pole Harness and Hardwire Kit - Includes Tester # C59496 if your splicing is correct when tested and yet your harness is not accurate.
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Brooks
11/16/2017
I forgot to tell you that the lights are on even if the truck is off. No other lights of any kind are on. The running lights on the truck are not on. Two places have said it is factory. So in other words. I would have to unplug the trailer evertime I’m not driving.