Okay, so this is actually a question about a '65 but more people visit this forum... I've got an old john boat trailer that I build a bracket for to extent it and carry a canoe. I'm painting it the same color as my truck and will be putting on the same tail lamp assemblies (so it will look really cool!) The problem is this bracket I made sticks out past the tail lights 3.5 feet, far enough for KDOT to say I need to put an orange flag on it. Rather than mess with a gawdy flag, I decided to install a third brake light. The problem is I'm not sure how to wire the thing!!! I have three wires, brown, green, and yellow. Brown is for park lamps. Yellow and green are your brakes/turn signals. Green is left, yellow is right (or vice versa, but that's not the point.) When the brake is on, both wires become live. When you turn on the signal, one wire keeps one light on while the other, of course, makes the other light flash. My issue is if I splice into, say, the yellow wire, that third light will flash when I'm turning. And if I splice into BOTH wires, I'm worried it will mess up the flow of electricity. How do you wire it so that the third brake is constantly on?
You will have to tie into the brake light feed wire that runs from your brakelight switch to the turn signal. It is a white wire on a GM. This will feed the third light whenever the brakes are applied without being influenced by the turn signals. You can also run a wire,each with a diode in them, from the yellow and green wire to the third light. This will let the t/s on either side flash and the third light to flash also if the brake ISN'T pressed down. As soon as the brake is applied the third light will glow steadily but the current can't feed over to the opposite side and it will continue to flash.
What Evan Said: They even sell such a thing with the diodes all ready inside it , called a " logic box " and most U-Haul places sell them . I'd imagine Pep Boys , Kragen , Schucks and so on all have them too but the counter dufus' might not know what you're talking about , just go look in the trailer parts section . Your planned rig sounds very nice ! .
