ev13wt

I have orange running lights. They have a single filament. They turn on at the first click of the switch.

I have blinkers (directional), and emergency flashers.

Now I want to build something that does the following:

When I turn on the running light switch, they should turn on. When I blink or emergency flash, they shall turn off when the blinker are in the "off" state.

They shall also blink, when running lights are off.

Relays, xand, diode? I am so stuck.

Oh, forgot: truck shall not catch fire and burn down.

p.s. While I could build a 4crawler solution with a double filament bulb, it only comes close.

RJR

For complex functions, I'd probably buy a $20 Arduino processor board, hook it up to a couple of big MOSFETS to do the power switching, and implement the logic in the Arduino. It's a lot easier to do complex logic in a microprocessor than with relays and switches.

At that, however, the hardwired version shouldn't be too hard.

- Replace your running light switch with a SPDT switch. Connect the center pole of the switch to +12. Connect the "A" output of the switch to the NC input to your flasher relay. Connect the "B" output of the switch to the NO input of the flasher relay. (It's very likely that your flasher relay has both of those inputs, even if they aren't both used.)
With the switch in the "A" position, current will flow through the NC input of the flasher and light the running lights. When the flasher activates and switches between NC and NO, they'll blink off and on.
With the switch in the "B" position, the lights will be off until the flasher switches to the NO position, in which case they will blink on and off. (Opposite phase to above)

A drawing would make it easier to visualize, but ASCII drawings aren't my strong suit.

RJR

Just for clarification:
NC = Normally Closed
NO = Normally Open

RAD4Runner

This is how I plan to do mine, if adventures do not get in the way of working on truck LOL!
Turn Signal and Park Light "source" are what normally go to them.
When turn signal is on:
1) Relay energizes and disconnects marker light power from lights.
2) Capacitor gets charged enough to keep relay energized.
3) Turn signal power connects to marker through diode, making them blink at same time.
4) Pin 87 (N.O.) contacts of relay send marker light source to optional side-facing lights to illuminate corner into which I'm turning.

ev13wt

Thanks so far. I can't replace the switch, must stay oem.

Using the unused relay input is very, very elegant. I'll check that.

RADs idea is nice - the side turning light could have an extra switch.

Lots to off of, thanks guys. I found some very cool online schematic drawing tools that even simulate what it's doing. I'll give it a shot tomorrow.

RAD4Runner

ev13wt,
I already tested the circuit^^^ but would take time to assemble, find where to interrupt the marker circuit and install.
If you have the chance, please help find where in the wiring harness the front markers and the rear markers join on each side. That's where we need to interrupt the circuit with the 87a contact of relay. We would then only need one relay per side.

I have the capacitor value somewhere on my receipts, and I actually HAVE 6A diode to go to marker and 3A to go to capacitor/relay coil. Would appreciate if anyone could chime in regarding diode current capacity for in-rush current for capacitor charging, but I'm guessing 3A should be enough.

As interim 30-minute solution, I connected negative side of fender-mounted marker and tail light to positive side of turn signals. They now blink but out of phase like Ron's results above would be, like on a few U.S. brand vehicles.
write-up here
Results here: