If you like me is annoyed by clown nose doing nothing but do not need/want to spend $400 on real BMW alarm than read on.

The following process is not complicated and can be done by almost anybody in a couple hours or so. You’ll need to put together a very simple electronic device. You can buy all parts from Radioshack for under $10.

Here is what you need:
TLC 555 Timer
Item: 2761718
Description: LinCMOS Timer
Quantity: 1 @ $1.69

Item: 2760159
Description: General-Purpose IC PC Board
Quantity: 1 @ $2.29

The rest of the parts I already had but if you need to buy them they are also available at www.radioshack.com.

For R1, R2 and R3 I used pot (adjustable) resistors. For C1 I end up using 1000mF capacitor.

The electrical diagram with pictures is bellow (the LED on a photo was for ease of adjustment since I had to go back and force from my car. I removed LED on board and replaced it with connections to LED in clown nose in a last step).

Next you will need to connect to the LED insight the clown nose.

There are at least two ways that I found to connect to it. First (the way I end up doing it): The LED (12V) insight the clown nose located on the rear view mirror. Mirror is attached to a black cover of rain sensor. The cover holds in place by springs which hold on to a hex bolt head permanently attached to the windshield (please see pictures and diagram bellow). To detach just twist (I did not have to apply a lot of force) the black cover with rear view mirror about 15-30 degree or so and it comes right off. The plastic cover is made of two separate inter-locking pieces. Insight you will find rain sensor plug at the bottom and LED plug were mirror is attached. I end up removing the LED plug and running two wires to LED directly thru wiring hose from light/sun-roof panel. Than I put everything back by twisting cover with mirror back in place.

Second way is to use existing LED wires which already go to the light/sun-roof panel. I think they were black and brown color but I did not want to spend time tracing them.

Last step: we'll need a 12V power that will be on when car is locked/not running and off when car is unlocked/running. Proceed to remove light/sun roof panel (you can find instructions on "how to" on this forum under DIY alarm installation). Insight you will see large white plug (1-20 connections), large black plug (1-20 connections) and a smaller black plug (1-14 connections) -- you need 1-14 connections black plug (see pictures bellow). There is a couple more smaller plugs (1-4 and less) that you don't need. On 1-14 connections black plug (wires are labeled 1-7, 8-14) the connection with number 1 behaves the way we need. It has 4.6V when car is running and after the car is turned off and locked in a minute or so the voltage changes to 12V. Interestingly enough if car is not running and you unlock it and wait about 3-5 minutes it also changes from 4.6V to 12V.
Connect positive (+) wire from the timer you built in step One to number one connection on 1-14 black plug and negative (-) wire to ground (I used bolt near motor).

Now, if you have a multimeter it helps. You can connect it in parallel to the timer and if you don’t it is not a big deal either. Adjust R3 so when there is 4.6V (car is running) the timer is off (LED is off) and when there is 12V (car is locked for more than a minute) timer is ON (LED is blinking). Adjust R1 and R2 to get desired timing/delay (how long the LED is On and Off). Note: the timer allows you to set up almost any percentage/delay you want. What I chose to do is to pull my car next to another BMW with factory alarm installed and matched the LED to that car.

Enjoy!

PS Please note there is a typo on a diagram - C1 is 100-1000uF