Aftermarket HID upgrades are becoming more and more commonplace, and as they become more popular, more people want to take it upon themselves to complete the installation. If you’re going to perform the modification yourself instead of having your car professionally serviced, you should be able to get everything to work just right if you follow the step-by-step guide below on how to install xenon lights on an E46. Just remember to disconnect the battery and turn off the engine before beginning.
1 – Along with your HID kit, you’ll want to purchase two additional holders. The holder should be designed to fit an H7 bulb, and should have an HB4 socket at the top. With extreme precision, cut through and remove the socket. Care is necessary as the holder is generally made from fragile plastic.
2 – Remove the female-end connectors from the holder as well as their plastic supports. Take the metal ring off as well with a pair of pliers. Whatever you do, do not remove the retaining ring that keeps the bulb in place.
3- With a power drill, cut a 22mm hole on the rear end of the adapted holder and smooth out the serrated edges.
4 – If the HID kit you purchased comes with a 12-volt connection, it is not necessary. The ballast itself should have a 12v supply plug that works with the HB4 connection, as you can tell on the wiring loom. On E46 models the 12v connection isn’t required, so cut off the spade connectors and pull out the wiring loom. Save the spare pieces for use later (just in case the lighting loom isn’t long enough to reach the ballast). The HID lamp base should fit now in the headlight housing, though you’ll have to make some adaptations to properly secure it.
5 – Make a cut in the holder retaining ring for the bulb and glide it over the cable cores (high voltage). You may need to modify the grommet by trimming it back so everything can fit and connect properly. Send the bulb and wires through carefully, and then pull the grommet out from the rear end. Next, push the lip of the grommet back in to seal the rear side of the holder.
6 – Adjust the wires and bulb until everything is in place on the base. Clip the retaining ring so that it sits back in the holder. The pressure from the bulb tab sitting directly between the two holder pins should keep the grommet and base in place.
7 – Find a flat surface for the ballast that’s far removed from the heat of the engine. Secure the ballast using a bracket or other retaining method. If you need to use tape to keep it in place, be sure to use two-sided, heat resistant tape.
8 – The lamp holder you modified earlier should fit with the HID bulb from the kit into the low beam assembly. From there, plug in the two high voltage wires.
9 – If the low beam loom doesn’t stretch long enough to reach the plug for the ballast, this is the time to adapt that saved wire from earlier to extend the connection. Connect any remaining wires and tie up any loose ends. If necessary, you can adapt an electrolytic capacitor to enable proper electrical flow to all of the new headlight components. Some users report bulb failure that occurs intermittently, and this is the best way to solve it, though a relay or resistor adaptation may also work. If everything has been done properly, you should have working xenon lights on your E46.