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off relay with delay on timer Answered

Hello smart people! I need to pick your collective brain. The project that I am working on is on my car. I am replacing the front turn signals on my car with an LED strip. The led strip has three wires. One for ground, one for white LEDs, and one for the amber LEDs.

If it is just directly connected to the current incandescent bulbs, the white comes on as a running light. When the turn signal comes on, the lights flash white, amber, white, amber..... (not what I want)

What I want it to do is turn off the white while the amber flashes, then turn the white back on.

I have a delay on relay, but that won't quite work for what I am trying to do. Isn't there a way to just throw a cap and resistor to keep the voltage on a relay to keep the white off till the amber is done flashing?


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5 years ago

Driving lights and indicators are a seperate circuit, they only share the common ground.
Nothing on the LED strip should be affected in the way you discribe it.

White should stay on (if the lights are on) and the amber should just flash.
But without any incandescent lamps in the indicator circuit it won't flash at the right speed and maybe even malfunction altogether.
If you add a diode to the positive wires of driving light and indicator they will be seperated for sure.
And if you turn off your driving lights for indicating I, if I were a cop, would have an excuse to stop and check you ;)


Answer 5 years ago

These aren't driving lights though. I am replacing the incandescent bulb with an LED strip. The incandescent bulb has two filaments. The first, a lower powered one, stays on as a running light. Then when a turn signal is used, the second filament lights up. I am tapping into the power for that bulb to run the LED strip. This will have a white light as the on, and then an amber as the turn signal.

I simply need a way to cut the power to the white while the amber is flashing, then restore power when done flashing.

I cannot picture the wiring from your description but I'll answer the relay delay question. Yes, you can use a simple resistor/capacitor network to keep a relay on. You could do the maths to work out the values needed but if you have a selection of parts on hand it would be quicker to figure it our by experiment. One thing to remember is that a relay has a hysterisis meaning that it will remain latched on at lower voltages than that which activates it.