In this video I take an L and spend 80 hours (and $80) building LED taillights for my 5 Series that ended up with a few annoying problems that render them pretty much useless. But despite this, I still vouch for this as a project and I reckon on the right car it could be really successful. You could also build these with a diffuser lens over the bulbs for a more even light output, but I wanted the look of the individual bulbs (facelift E46 vibes).
Technical details:
LEDs used: 4.8mm diameter wide angle LEDs (about 15c each)
Clear lens LEDs for:
- Running light (approx. 50 per side)
- Reverse light (approx. 35 per side)
- Indicator (approx. 60 per side)
Red lens LEDs for
- Brake light (approx. 45 per side - this tinted version was slightly brighter than clear lens, so I chose it for the brake light)
Resistors (about 3-5c each)
- 330 Ohm for red and amber LEDs (LED voltage about 2.1V)
- 180 Ohm for white LEDs (LED voltage is higher for white, about 3.3V)
Wiring: see diagram in video
- If your module uses a number of LEDs not divisible by 3, make a couple of the clusters a set of 4 if needed. The brightness of the cluster will barely be any dimmer than the sets of 3. Do not run any LED clusters in groups smaller than 3 - they will most likely burn out immediately
3D Printed inserts: I designed these in Fusion 360, I had to experiment a bit to get them fitting well, although there is still a little room for improvement. I have made the files available on Thingiverse via this link:
- 3D Printer used: Bambu Lab X1-C
- Filament: ABS or PETG
- Printed at about 50% infill with a skirting raft at the base
Adhesives:
- Clear roof and gutter silicone (black would be better in hindsight)
- Loctite Extreme Glue
- Generic superglue for keeping LEDs secure inside the printed modules (if the superglue creates a fog on the surrounding plasitc, you can use a black Sharpie to conceal it, it won't be noticeable behind the lens unless it is a crystal clear Altezza-style lens. Wait at least a few hours for the superglue to release any gas before sealing the lens, so that it doesn't fog the inside of the taillight).
Reflector: Generic exterior reflector used behind the lens, as the reflector along the bottom of the lens became damaged from cutting the lights open. This reflector works fine behind the taillight lens and is fully functional.
Paint:
- Duplicolor Trim and Bumper paint - Black
- White Knight Squirts - Satin Black (for border around lens)
- Balchan professional acrylic lacquer paint - Clear Gloss
Load resistors: generic 50W 6 Ohm load resistors (avoid if possible)
Good luck!