E39 Xenon Retro-Fit Resistor Packs

Prepared by VietSB
Modified 09.28.03

NOTE: Perform these steps at your own risk. All P/N's listed are a "best guess", so please double-check with your local dealer. These mods and repairs were performed on my US-spec 1997 540iA (11/96 prod date, M62 engine) but there is no guarantee they will work on other E39's. These instructions are provided for entertainment purposes only!
BACKGROUND: Some E39's originally outfitted with Halogen head lights will perform a "cold scan" to determine the status of the low-beam bulbs by checking the resistance of the filaments while the lights are off. Since Xenon bulbs have no filament, they will trigger the dreaded "CHECK LOWBEAM LIGHTS" warning message. Unfortunately, we've seen no pattern as to which years or models of E39's will require the resistor packs.

Anyone thinking of retro-fitting Xenon lighting to their E39 should run this simple test to determine if resistor packs are required:
Unplug one of your low-beam harnesses from the bulb and try cycling the ignition a few times with the seatbelt fastened to clear that MID message. To be absolutely sure, you should take a short drive during the day, again with the seatbelt fastened, and if you never get the check message you might be fine without the packs.

Required Parts:

Required Tools:

Recommend Tools:
I purchased the Hella packs since I'm lazy and wanted a guaranteed plug-n-play. They come with no mounting instructions or hardware. Instead of zip tying them to the outside of the ballast, I decided an inside install would be cleaner. I removed the (2) or (3) 8mm bolts and nuts (don't let them fall!) that hold the ballast brackets in place, unplugged the harnesses, and removed them from the car. The inside section of the bracket has two tabs that are meant for ballast cable management. I have a different cable routing method, so I flexed them with some pliers till they snapped off (shown in foreground of pic below) to make room for the resistor pack. Two well-placed zip ties and they are secure.

You can see it's a pretty clean install location. The brackets will need to be removed to change the high-beam bulbs, but I think that's the case even without the resistor packs positioned there.

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