2G Old school sequential tail light setup

[jesse12345]

I have a question on how to run resistors to the tail lights to make them essentially sequential?

I'm not changing anything to LED just the old school stock bulbs. My buddy somehow did it to his old Eclipse which is now mine. He used this weird deal that has 5 wires that come out of it. I just don't want to rip all that out, I'd rather try to wire up my own deal I'm just not real sure how I'd make them work in series.

I'm still trying to learn this stuff and research constantly but I hit road blocks that need to be kind of dumbed down for me every once in awhile.

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[jesse12345]

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[curt-s]

Resistors won't do it alone as resistors just reduce amperage through a circuit by converting the energy into heat.

You'll need to independently light each bulb in sequence. My guess is that doohickey device used a 555 or 556 timer at minimum but whatever else, not sure.. halogens take a relatively large amount of current.
Other methods I've seen are a combo 555 and 4017s with diode arrays, but we're only talking about a couple bulbs here so it could be much simpler than that.

You'll also have to deal with turn signals, brake lights, running lights, etc. as the bulbs are shared amongst these functions in differing ways. Most systems solve this by using diodes.

 

[jesse12345]

So its not going to be as easy as what he did with whatever gadget he hooked up?
All I know is everything works completely normal and I wish I knew more about this stuff.

 

[curt-s]

If his gadget works and you were to use it, it probably would.. if you know what each wire does. I'm just not sure what components that gadget is made of. All I'm saying is you can't do it with resistors alone. You have to use other discrete parts as well

 

[jesse12345]

Oh okay so resistors alone won't do whatever this deal is doing. Everytime I look up how to do this it always shows leds or something to that nature which I really don't want to use. I also don't want to cut them out just to use in my other car.

 

[curt-s]

LEDs use a lot less current than halogens so you can get away with smaller rated components but even a standard NE555 can only sink or source around 200mA of current.. you're likely still going to need a MOSFET or relay to control each bulb.
A low side N channel MOSFET capable of 10A or more is what I would personally use. Vgs of 10V will work fine with automotive. Vgs of 4.5V if you're doing logic level stuff.
Of course you need the rest of the circuit as that's only one component. A 555 or 556 for timing, something to keep A,B and C bulbs lit in their sequence, diodes to override for brakes..
Then you have the situation where your turn signal and brake both need to be on. Usually brakes will then turn off for the side that is indicating. Or your brake can be ANDed with to create an overall voltage waveform that produces a half cycle for when the indicator isn't lighting the bulbs and 100% for when they are.
It can be fun to figure out. I approached my old set using the Arduino method as it allowed complete timing control. But I had 7 segments and 273 LEDs per side so it was a lot more complex than a halogen sequential flasher.