flashing side markers

[Stephen717]

i know some minor wiring but was wondering how do I get my front and rear side marker lamps to alternate so that when the turn signals on the front and rear of the truck are dim the side markers are bright and vice-versa. any help would be much appreciated.

thanks
trip

[dmjlambert]

Are you talking about the way I have mine as described in this thread and video? I believe this is appropriate for the front markers, the back markers just turn on with the parking lights and do not normally blink.

http://67-72chevytrucks.com/vboard/s...=707545&page=2

[Stephen717]

The rear side marker lamps never blinked from the factory but I wanted to do something a little different. I would like both the front and the rear side marker lamps to flash like in the video though.

[dmjlambert]

Try it. The basic idea of the front marker if you have it wired as a combo marker and blinker, is:

The side marker bulb is connected to the parking lamp signal. That parking lamp wire is either at 12V or at ground potential, depending on whether the parking lights or headlights are on. The other side of the filament is connected to the flasher signal. That flasher wire is either at 12V or at ground potential, depending on whether flash is on or off.

If you have the parking lights or headlights off, the side marker bulb is connected to ground and the flasher, so it works as a flasher bulb and does the same thing the front parking light does.

If you have the parking lights or headlights on, the side marker bulb is connected to 12V and the flasher. When you signal to turn, when the flasher signal goes to 12V, both sides of the side marker bulb filament are at 12V, so no current flows and the side marker is off. When the flasher blinks off, or if you are not using the turn signal, the side marker light glows.

I don't know if the combination brake and flasher signal at the rear of the truck would work in the same way. It depends on whether the turn signal switch is designed to send the brake and flasher wire to ground when it is not at 12V. It probably is not designed that way. But you could try hooking it up in the same way I show for the front side marker and see what you get. If it does work, it is likely that when you apply the brakes and the headlights are on, the side marker lights will go out.

You may just want to run the wires from the front side marker lights to the rear of the truck. Wire the left side marker lights in parallel with each other, and wire the right side marker lights in parallel with each other. That would simplify it. 4 extra wires going from the front to the back of the truck.

Really you could use just 2 additional wires from front to back, because the parking light signal is the same in the front and back of the truck. Brown wires at the back of the truck, and purple wires at the front parking lamps are the same signal I believe. Take 2 aspirin, study the heck out of the wiring diagram, and wire it up. Or skip the aspirin and just use 4 wires....

[Stephen717]

never thought of piggybacking the wires from the front side marker lamp to the rear. That would probably work better than trying to figure out everything in the back of the truck and would make the wire easier to get to if I ever have to replace it. Thanks