How do I wire this to keep a constant solid light, then flash when brake pedal is depressed?

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I don't believe that you can with those devices.

The one I have just goes inline with the 3rd brake light. I can choose many different modes, number of flashes, speed, etc. But it's either on or off. There's no 'running light' setting.

I have seen other LED lights where the brain is contained within the light itself. There are many more wires so that you could do what you're saying re: running light and brake light. There may be pulse flashers on eBay that will do this too. But with only two wires going to the module; I don't see how it could do both.

 

I feel like it miiiiiiight be possible. Besides the fact that my car might blow up, I feel like if I somehow make a Y connection with the brake signal and power source to the relay, the signal can tell the relay to cut off to make it blink. Gonna buy a couple extra fuses and play around with it lol

:rotfl: hopefully it works, but I'll will update once it does for anyone that is also interested

thanks for the insight shoegazer

 

Okay.

My prediction is that you'll end up zapping a 12 volt LED with 24. The LED unit may end up being toast. But hopefully your tail light/brake light system will survive.

You can go buy a couple of 12 volt lantern batteries at Wal-Mart and test this on a bench. Or just get a couple of 12 volt adapters that plug into the wall.

The LEDs draw so little amps that you may even be able to wire up smaller batteries to equal 12. Most AAA, AA, C, and D cells are 1.5 volts each.

Good luck. And shoot a video if you can.

 

Simple solution:
2 inputs: parking light wire, and brake light wire.
I believe the minimum parts you need is a SPDT relays and a flasher unit.

It is wired so when the parking light is on, the "forth brake light" is on.
When brake light is on, the relay cuts the power source from the parking light and instead gets power through the flasher unit.
Something like this:

B is brake light, P is parking light.

If you want the parking light mode to be dimmer, add a dimming circuit to the parking light source.

 

oh man, this is god damn phenomenal! I really appreciate the help Bath Tussue. Going to attempt that after I order a couple relays. Found a whole lot on ebay with pig tails included too! Oh man, that just made it a lot easier

 

That would work