So as I was driving home last week I was behind a newer car that everytime they hit their brakes the third brake light would blink. I thought this was very cool and definately got my attention (the whole point, kind of like daytime running lights). So I set out to do the same to my 2009 E90.
Something that I did not like however was that everytime this person hit thier brake lights it would flash. In stop and go driving this would get very annoying. So I wanted something that would flash on initial hit, but then not keep flashing.
I had read that there is a way to code your car so that it will flash the brake lights when you SLAM on the brakes, but that was not what I was looking for as the couple of times I have been rear ended I WAS aware of the car in front of me and slowed down appropriately while the person behind me did not. So I found this site KAHTEC (google search) that sold several differnt modules and upon reading I found their Blink Smart Stop Delayed version. This delayed version blinks the first time you hit your brakes but if you hit them again within 8 seconds it will stay solid and not blink. So in stop and go traffic this would be perfect!
Beer (better slam them back because this mod takes no time at all)
Double Sided Tape
So I picked up the KAHTEC.com Blinking Smart Stop Dealyed version. At only $24.95 I thought this to be a great cheap mod. Only takes about 15 mins to install and does not produce any error codes.
Picture of said item
So start by removing the rear cover for the third brake light. Start by pulling down in the back first (Labeled #1 in pic) then pull towards the back as indicated by arrow #2.
For reference and so you can see how the tabs work...
After you remove the cover look for the gray connector to the right.
Push down on the top of the black plug for the two wire connector with the Black/Yellow stripe and Brown wires. Pull this out so that you can work with it.
The module comes with way more wire than what you need for that space. So I cut all but about 4.25" off of the module.
Also while you still have it out of the car go ahead and use some Acetone and clean one side so that your double sided tape will adhere to it.
Now cut off a little piece of double sided tape and apply to your now clean module. I used the heavy duty 3M stuff that you can get at Lowes that can hold 20lbs Also just so happens that this stuff is the perfect width for the module.
Now back inside the car...
Take your clippers and cut the Black/Yellow Stripe wire leaving room on both sides of the wire. The wire coming from the chassis will now go into the red wire of the module. The blue wire will now go to the Black/Yellow Stripe wire that leads into the 3rd Brake Light. Finally the black wire simply taps into the brown wire for a good ground.
Here is a diagram that I made so that you can see where the wires go. The Black/Yellow stripe is the positive, the Brown is the negative wire.
Your setup thus far should now look something like this:
Now beside the FM/AM antenna module there is a perfect location for the KAHTEC module to be mounted. Take your acetone and make sure that the area of the car that you will apply is clean as well. Then take off the other side of the tape and apply next to the FM/AM module.
Replace third brake panel and thats it!
Go out and enjoy the attention your rear end will now get
Youtube video of my car in action. First apply brakes to show blinking light, and then hit the brakes again within 8 seconds to show that it will go solid. Then wait a full 8 second and apply again to show blinking.