1157 Conversion Bulb Holder for BMW e28 - Tail

This is a replacement bulb holder for e28 BMWs that allows you to convert the rear-facing lights to 1157 dual-filament bulbs for improved rear visibility, without modifying the factory wiring harness or tail light housings. This model fits the Tail light bulb socket. I have another model that fits the Brake, Fog, and Reverse light sockets, which is slightly different. You will need one of these and two Brake light sockets for each side of the car.

Note: These require generic 1157 bulb holders of the design that has holes for two screws on the back plane, as well as M4 button head socket cap screws and nuts to assemble. You will also need to make a simple wiring harness to hook them up, examples are shown in pictures. The left-hand side is shown, the right-hand side is mirrored.
 
WARNING: The example wiring shown is meant for use with LED bulbs. Standard filament bulbs require a relay harness in order to not exceed the load rating of the factory wiring. Failure to heed this warning may cause a fire! I TAKE NO RESPONSIBILITY FOR WIRING ERROR, OR ANY DAMAGE THAT MAY OCCUR AS A RESULT. If you don't know what you're doing, get help from someone who does!

Full required parts list for a whole tail light (3 sockets):
2x 1157 Conversion Bulb Holder - Brake 
1x 1157 Conversion Bulb Holder - Tail (this model)
6x M4x16 button head socket cap screw
6x M4x10 button head socket cap screw
18x M4 nut
3x generic 1157 bulb socket
8x small ring terminal (fits around M4 bolt)
2x butt-splice crimp connector
Approx. 3 feet / 1 meter of 14AWG automotive hook-up wire
Heat-shrink tube (as needed, your preference)