The following DIY documents my 3rd brake light installation procedure for the US Ariel Atom.
My lawyer wants you to know this:
Do not use this DIY unless you are familiar with basic automotive repair procedures and safe workshop practices. This DIY illustrates the workskop procedures required for the specific subject being documented in the DIY. It is not a substitute for full and up-to-date information from the engine and vehicle manufacturers, nor is it a substitute for proper training as an automotive technician. Note that it is not possible for me to anticipate all of the ways or conditions under which vehicles may be serviced or to provide cautions as to all of the possible hazards that may result.
The engine and vehicle manufacturers may continue to make changes, issue service information updates and parts retrofits after this DIY has been published. Some of these updates and retrofits will apply to procedures and specifications in this DIY.
I have endeavored to ensure the accuracy of the information in this DIY. Please note, however, that I cannot warrant the accuracy or completeness of the information contained in this DIY.
FOR THESE REASONS, I DO NOT MAKE ANY WARRANTIES, EXPRESS OR IMPLIED, THAT THE INFORMATION IN THIS DIY IS FREE OF ERRORS OR OMISSIONS, AND I EXPRESSLY DISCLAIM THE IMPLIED WARRANTIES OF MERCHANTABILITY AND OF FITNESS FOR A PARTICULAR PURPOSE, EVEN IF I HAVE BEEN ADVISED OF A PARTICULAR PURPOSE, AND EVEN IF A PARTICULAR PURPOSE IS INDICATED IN THE DIY. I ALSO DISCLAIM ALL LIABILITY FOR DIRECT, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES THAT RESULT FROM ANY USE OF THE EXAMPLES, INSTRUCTIONS, OR OTHER INFORMATION IN THIS DIY.
Your common sense and good judgement are crucial to safe and successful service work. Read procedures thoroughly before starting them. Think about whether the condition of your car, your level of mechanical skill, or your level of reading comprehension might result in or contribute in some way to an occurrence which might cause you injury, damage your car, or result in an unsafe repair. If you have doubts for these or other reasons about your ability to perform safe repair work on your car, have the work done at a qualified repair shop.
Now that that's out of the way, installing a 3rd brake light (or CHMSL - Center High Mount Stop Lamp - in technical terms) isn't complicated and may help you pass an inspection at your DMV, as well as possibly preventing stops on the road for not having one. Additionally, a NHTSA study shows benefits from the CHMSL.
Each of the images is clickable to display a higher-resolution version.
This is the brake light kit I used. It is a Hella model "2DA 007 541-001" and the Hella catalog page can be found here. A convenient US source for this lamp can be found here (part number HL23102).
I also used some Thermo-Shield heat protective tape to protect the wires (this is the same heat tape that Brammo uses).
This is a picture of the light as installed on my Atom. While it is hard to discern in this picture, the housing is painted the same color as my Atom body panels. The Hella kit includes detailed instructions for your paint shop when painting the housing. The factory finish is a glossy gray color, so you'll probably want to paint it, either the color of your body panels or black.
Installation is straightforward, involving drilling one hole in the "tea tray". Complete instructions are provided with the light kit.
My tea tray isn't really this filthy - honest! It is just the angle of the picture and the bright flash I used.
This is the view that people behind you will see.
I have covered the wire with heat insulating tape to protect it from the heat of the muffler, which is right below it. Extend the tape to the diagonal tube member on the right side of the car.
Since the light is attached to the "tea tray" which tends to be removed for various maintenance purposes, I installed a mating pair of 2-pin GM "Weather Pack" connectors. These are the same style used elsewhere on the Atom, and are available from a large number of vendors. Of course, you can use whatever connectors you like.
Route the free end of the cable down the diagonal tube member to near the right rear tail light assembly. Use a tie wrap at the top and bottom of the tube to support the cable.
Now, you need to get into the tail light harness to tap power for the new light. I disconnected the 4-pin connector by removing the red latch pin and pulling the connector halves apart. I then unwrapped the electrical tape protecting the wires coming out of the tail light housing and slid the woven loom up the cable to give me some room to work.
I then used the quick-connect fasteners that came with the light kit to tap into the black wire (ground) and the green wire (brake light). I staggered the two quick-connect fasteners so that when I was done, I could slide the woven loom over the fasteners. I then replaced the electrical tape on the end of the loom and re-connected the connectors and installed the locking tab.