Picture of Neat Turn Signal Effects Circuit
Ever wanted some cool turn signal effects, but thought they were just for Caddies and Beemers?


For about $25, this weekend project can turn your marker lights into a sweet set of turn-marker-combo lights!

Description of what the circuit does:
This is assuming your car has corner marker lights that are separate from your turn signals.
The circuit flashes the marker lights with the turn signal, regardless if the marker lights are turned on or off.

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Step 1: The Goods

Picture of The Goods
What do you need?

- basic soldering skills
- basic automotive skills
- basic electronic skills
- mad air-guitar skills (just kidding)

- soldering stuff (solder pencil, solder, helping hands, heat sinks)
- knife (used for stripping wire)
- wire strippers
- needle-nose pliers (helpful)
- hot glue gun
- heat gun

- electrical tape
- 14 to 16 gauge wire, about 12 feet
- 2x capacitor(s) (about 6800 µF)
- 2x diode (rectifier type, 2 amps or higher)
- 2x automotive relay , SPDT (the one with 5 terminals)
- 2x relay socket
- 8x heat shrink butt connectors (blue)
- 4x crimp tap connectors (blue, available at WalMart or RadioShack)

Step 2: The Cap(s)

Picture of The Cap(s)
I didn't have a single 6800 µF capacitor, but I did have a 2200 and a 4700, which in parallel add up to 6900, which is close enough for me. If you are using LEDs, you may want about 3000 µF.

If you use two capacitors like me, this is the step for you. If not, go ahead one step.

1. Solder the capacitors in parallel.

that's it

Step 3: The Diode

Picture of The Diode
Tape the capacitor(s) to the relay holder.
Solder the diode in as shown in the picture. Be sure to heat sink it!
Then solder the relay coil "+" wire to the "+" side of the capacitor(s).

Step 4: Wiring

Picture of Wiring
Pictures are better than words here, so click through...

Step 5: Weatherproofing

Picture of Weatherproofing
Apply gobs of hot glue to all exposed metal to seal out moisture and dirt. You can probably get better results if you use something like Plasti-Dip, but I didn't have it.
ianrab (author) 4 years ago
Video of the circuit in action:
skwoorl3 years ago
I'm wondering would this circuit would work for led marker lights or only incandescent bulbs.
ianrab (author)  skwoorl2 years ago
Yes, the circuit should work fine for LED bulbs. You may need to also install an electronic flasher (cheap, search for "electronic turn signal flasher" for your car). I plan on adding this effect to my trailer, using the amber bulbs on the side.
l8nite4 years ago
Maybe new cars are different and I admit its been a long time since I was a volunteer fireman but we just ran a wire from the turn signal to the side marker lights, or to make the marker flash out of time with the turnsignal we ran a switched flasher fuse to the marker or fog lights. That being said, I enjoyed reading your ible
ianrab (author)  l8nite4 years ago
ianrab (author)  l8nite4 years ago
Thanks. Yeah, that does sound easier. The only issue with the one-wire method are that it would turn all the running lights on with the flasher. That means the instrument panel, rear marker lights, and whatever else comes on. It just wouldn't be noticeable unless it was dark out, but those lights would be on anyway.

And this actually replaced a circuit that I had in before. It alternated the marker light and turn signal if the marker lights were on. The relays rusted out, so I wanted to do something a bit different.
Phil B4 years ago
Thank you for a nice Instructable. I do not know that I will do it on my car, but I enjoyed reading about what you did.
zazenergy4 years ago
What a cool mod!
ianrab (author)  zazenergy4 years ago