Please bear with me as this is my first attempt at a DIY
My earlier post showed LEDs in my dash and I was asked for a DIY, well here I go.
1. selected the LEDs I wanted to use, I selected High intensity Blue LEDs. I got their operating voltage and desired current and applied it to the formulas at this link http://www.metku.net/?sect=view&n=1&path=m...dcalc/index_eng
that allowed me to figure out the current limiting resistor I required.
In this case I created 4 small circuit boards and fed them from on 12 v source.
2. after obtaining all the parts required I used a printed circuit board kit from radio shack to build 4 identical boards that would just cover the light holes in the instrument cluster of my 320i. I think they were about 1 1/2 in by 1 in. I traced the lines out on the boards and etched them in the solution that came with the kit.
Info on this is available in the kit. see the crude attachment sorry about that
when making the boards I ran power to the board which was then fed to a resistor ( in this case a 633 ohm resistor) this then fed the LED in series.
I assembled each board and provided enough wire to connect the power and grounds
3. I removed the dash from the car and set up a small 12 volt battery to set up the aim of the LEDs (leave enough leg on the LEDs to allow you to bend them to aim)
4. after having the set up correct I then used clear silicone to mount them to the top of the cluster unit so that the LED just hung through the opening. Caution should be observed not to knock the aim of the LED off while mounting them.
5. after mounting and drying I removed the bulbs from inside the dash and connected the power wire to the hot line on the bulb socket
other than that I need a few days and a better drawing program to give you a good drawing if one is needed