Photos and Article By: Chris a.k.a. "CelticNut"

The Installation

With a little help from the good people at WebElectric Products, I was able to equip my Mustang with an awesome set of Sequential Taillights!

To complete this conversion you need the year specific wiring harness for your vehicle (for the 2005+ mustang the part number is STS-1M5PW), a deep-socket or box-end 7/16" wrench, and a small flathead screwdriver.

Once I obtained the proper harness, I found the installation to be pretty simple. Here are a few pix of my little project, and some simple recommendations to help make this mod go smoothly:

1: This is what you'll find once you remove the inner trunk trim. Two thumbscrews and four small tension clips keep it in place and are easily removed.
2: Here's the passenger's side
3: And the driver's side
4: Use a deep-socket 7/16" or box-end wrench to remove the 3 nuts on each side.
5: It's pretty tight in here, so be careful not to get scratched!
6: Use a small flathead screwdriver to pop the clip on the factory wiring harness connector. Exert gentle pressure on the top tab of the clip.
7: Gently pull the taillamp assembly away from the car once you've pushed the harness and grommet through the opening in the sheetmetal. You may want to keep a towel handy. Place it on the bumper to prevent accidental scratches.
8: Here's what your ride looks like without taillights. No turning back now!
9: Place the taillamp assemblies on a soft cloth or clean carpeting while working. This will protect them from scratching. Here's the old wiring harness, unplugged from the assemblies.
10: Here is the taillamp assembly with the sequential harness installed. NOTE: This harness (Part Number STS-1M5PW) actually turned out to be the earlier version; I have since replaced it with the newer one. It is similar in design, but has slightly different sockets. For the sake of simplicity, assume this one is correct. The light bulbs were transferred from the old harness to the new. The sockets unscrew from the taillamp assemblies using a counter-clockwise motion.
11: Here are the two taillamp assemblies, ready to be reinstalled. Note the small black cylindrical modules...that's where the "magic" happens. They are the electronic control units.
12: Webelectric supplies you with small wire ties to fasten the control units to the harness, but said you could also use electrical tape. I opted for the latter...
13: Once you've tested the blinkers, flashers and brake lights, you're ready to button things up. All you've got to do is reattach the inner trunk liner. It's as easy as that!
14: Another view of the trunk liner, returned to its proper place.
15: You'll notice that the trunk liner fits snugly against the weatherstripping and the soft felt trim. Use that as your guide when making final adjustments.

The harness used for our installation is the STS-1M5PW and works on 2005+ Mustangs. The folks at WebElectric Products were great to deal with. I recommend them highly. Visit them at: http://www.webelectricproducts.com