How to install LED brake lights

[atomic80]

For a long time after hearing about different folks who have tried putting in LED bulbs in their M5's only to face an error message in their dashboard. This was because of the different amperage required by the LED lights as opposed to regular incandlescent bulbs. Total current required by the LED bulb is 90mA at 13.8 Vdc -Verses- 2.6A for incandescent. I happened to stumble upon a possible solution thanks to a friend from the MB board. An elegant solution presented itself in the form of using an aluminum based load equaliser (comes with blue quick connectors from 3M)($5) and a set of red LED bulbs at $38 a pair. Both can be purchased from Myroadster.net. You'll need a load equaliser for each brake light. I did not put one in the third stop light because the bulb goes in vertically and the LED bulbs are directional meaning that they would not be that visible from the sides. Another thing to note is that you can also get amber LED bulbs for the turn signals. One of the nice thing about using those LED bulbs is the fact that they remain clear when they're off so you would not need silvervision bulbs. I haven't tested those so I can't tell you if this will work or not. I do know that you would need additional load equalisers for those too. Only one per side (driver and passenger). You would not need to put a load equaliser in the front and rear for the turn signals since they're on the same circuit. One other good piece of good news is that the HID foglights still work too.

Main benefits of getting LED bulbs:

1) They light up instanteously (no delay for filament to glow on/off)
2) Safety
3) Very red compared to incandlescent
4) Looks good

Images (Be sure to click on each image for the original image)

Twin LED brake lights with incandlescent third brake light. - fast exposure time.


Twin LED brake lights with incandlescent third brake light. - slow exposure time.


More images can be found here.

Instructions on how to install them (refer to the album for images):

It should be noted that these instructions are for M5's with the newer LED type taillights. You'll also need a plier, 4 tiedowns (zip ties) and a scissor/wire cutter.

1) Pop open the cover on the driver's side. Replace the incandlescent bulb in the brake light with the LED bulb.
2) Unplug the connector attached to the taillight assembly (push down on the tab on top and pull straight out)
3) Look at the connector end and you'll see numbers from 1 to 6. On the driver's side what you need to know is the brown (common ground) and the brown/black (positive) wire. Those are marked #1 (positive) and #3 (ground).
4) It does not matter which end of the red wire from the connector you put in the middle of the blue quick connector and then put the outside part on the brown/black wire. It's a bit tricky so take it easy and go slow. After you've gotten everything lined up, use the plier to push down on the metal piece on the quick connector and then lock the plastic tab into place. Do the same thing for the brown wire with the other red wire on the other side of the load equaliser. On the passenger side, its blue/black #1 and brown #3.
5) After you've put the load equaliser in place, use the tiedowns to secure the load equaliser in place so that it "floats" without touching any of the other wires. This is necessary because the load equaliser gets searing hot (they're designed to do that)!
6) Double check everything and cut the extra length from the tie downs.
7) Test the lights. You should not get an error message in your dashboard anymore!