Ever wanted some cool turn signal effects, but thought they were just for Caddies and Beemers?

LOOK NO FURTHER!

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

http://www.youtube.com/embed/mDSxSAiZOlE

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.

Step 1: The Goods

What do you need?

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

Tools:
- 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

Materials:
- 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)

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

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.

Step 6: Repeat

Yeah, that's right. Make another one. One for each side (passenger and driver). But don't worry, you're halfway there! High-five!

Step 7: Done! (with the Circuits)

That's right! now just to install them somewhere in the car...

So grab a cold one (or whatever refreshing beverage you like) and enjoy the success of having completed the most tedious part!

Step 8: Attach to the Car

So where exactly does this attach to the car? Well, I'll tell you.

(all wire colors are in reference to my project. if you used different colors, use those)

First start off by finding the positive and negative wires for both the turn signal and marker light.
Cut the positive wire to the marker light.
Attach the YELLOW wire to the bulb positive.
Attach the RED wire to the marker light source positive.
Splice the BLUE/GREEN wire into the turn signal positive.
Splice the BLACK wire into the turn signal negative.

All connections are crimped to avoid hot solder burning stuff. They are heat-shrunk to seal out the elements
Test before re-assembling.

Step 9: Final Pictures and Video...

...along with application ideas.

I'm using this circuit for my front turn signals, but you can easily use this for brake lights, side marker lights, and just about any light on the car. Also, this can be used for wiring trailer tail lights.

HAVE FUN!!!
(post some pictures of your set-up, if you want)

UPDATE: I recently made a trailer light controller using this circuit. It's a lot easier when you only need to make one trip to Radio Shack...
<IMG SRC="http://i1179.photobucket.com/albums/x388/irab88/CIMG7509.jpg" ALT="Trailer Light Controller">

(disclaimer: I am not responsible for anything you do. I will not pay your ticket if an officer pulls you over for a STREET LEGAL modification. It's your car. I will not pay your medical expenses (if you get shocked by the capacitor or burned with hot glue or...), as I already had to pay for mine. Be safe, be smart.)