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

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 3: 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

Pictures are better than words here, so click through...

Step 5: 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) 3 years ago
Video of the circuit in action:
skwoorl2 years ago
I'm wondering would this circuit would work for led marker lights or only incandescent bulbs.
ianrab (author)  skwoorl1 year 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.
l8nite3 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)  l8nite3 years ago
ianrab (author)  l8nite3 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 B3 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.
zazenergy3 years ago
What a cool mod!
ianrab (author)  zazenergy3 years ago