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Old 02-18-2024, 01:57 PM   #21
RustyPile
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Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,605
Re: Getting brake lights to work

To solve this problem, you'll definitely need a wiring diagram, and the knowledge to read it. If this is beyond your skill level, find someone locally to help you.

There are 2 power sources for the rear turn signals and brake lights and both of them enter the turn signal switch at 2 different points.. Starting at the brake light switch, the orange wire (hot all the time) brings power to the switch. When the pedal is depressed, that power is applied to the white wire where it is carried to the turn signal switch. When the T/S switch is OFF, this power passes through the switch and back to the brake lights through the dark green wire (right side) and yellow wire (left side) brake lights..

The 2nd power source is the purple wire (hot only when ignition switch is ON) coming from the flasher unit on the fuse box. It goes to the turn signal switch and is picked up as a power source only when the turn signal switch is activated for either side.. From there power is passed along the dark green wire or yellow wire, depending on whether RIGHT TURN or LEFT TURN is selected...

None of the circuits are connected to any other lighting system.. If the wiring harness has errors in its construction or there are errors in its installation, there is NOT a set of instructions for locating these errors. Only diligent troubleshooting while referring to the wiring diagram will find the problem.. The problem can be exasperated by a change in the color coding of the wires... I have the tools, skill, and knowledge to construct wiring harnesses using proper gauge and color coding.. Therefore I have zero experience with any of the aftermarket harnesses.
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