E34 HID low beam error fix-bulbs and resistors [Archive] - Bimmerfest - BMW Forums

: E34 HID low beam error fix-bulbs and resistors

10-31-2008, 10:13 AM
E34 HID low beam error fix
There has been a lot of discussion over how to eliminate the low beam error we see on many e-34s when we convert to HID lighting. The following techniques worked for me on my 95 BMW e34 built January 95. Your experience may be different. I am beginning to suspect the later models are subject to this error more than some of the earlier models. Also, the error may be very dependent on the brand of HID system. I just do not know. FYI, I purchased my HID 55w 4500k 9006 system from http://www.ddmtuning.com/. Very good price, very good pre and post sale service with a lifetime warranty. Call them rather than e-mail.

Key is to be prepared in case you get the error. IMO, I would discuss your concern with your HID vendor BEFORE you purchase the lights. If you buy the ultra cheap light on e-bay, you may not get very good pre-sale or even post sale advice.

I understand some HID vendors sell products that may eliminate the low beam error problem. This may be your best solution. However, they do not always work on every car. Therefore you may need to DIY

I have experimented with two low beam fix techniques and both worked for me. The ideas for these techniques came from several postings on the various BMW forums. Many postings left a lot to the imagination on how to complete the task or were complicated with relays, LKM hacks, capacitors and/or extra wiring. If you are not well versed in automotive wiring and/or electronics you just might hesitate.

Technique One-use a small light bulb
The first technique is very simple in concept. Install a light bulb to simulate a bulb (filament) in the circuit for each headlight to fool the Light control module (LKM) into thinking there is a real low beam halogen bulb in the circuit. HIDs do not have filaments. I learned of the bulb idea from bo525i at http://www.bimmernut.com/forum/showthread.php?t=39714&highlight=side+marker+hid.

I simply soldered 22 gauge wires to a 5 watt side marker wedge bulb (2825 or 2825LL) and connected it across the headlight connector on each side (positive & negative). See bo525i's illustration in his post. The 9006 bulb connector looks a bit different. Same concept

This creates a parallel circuit with the side marker bulb and the normal headlight circuit... Actually, I think even a lower wattage bulb will work.
If you have access to extra side marker light wiring with a bulb connector, possibly any small bulb connector would work, use it. As the e34s side marker bulbs will only last 300-600 hours, a socket will enable you to replace without re soldering.

I covered the bulb with shrink wrap so not to have any light under the hood area and to somewhat insulate the area from the hot bulb while protecting the bulb from water.

Now you can connect the device several ways.
First you can use 3M red Scotchlok "tap on" connectors and not modify the wiring except the insulation is cut... No insulation needed, especially if you use some sort of water resistant connector.

Second technique is to trim insulation off the headlight connector wires and solder in a connection to the side marker light. Tape or insulate as needed

Third technique is to insert your side marker bulb wires into each side the female portion of the headlight plug and then connect the male portion of the plug. If you use the 22 gauge wire you can barely press fit the plug to get a good connection. May need to use insulation tape to insure a water resistant connection. The last technique is what I did to test a "proof of concept". It worked for me. No modifications to any of the existing wiring.

Technique Two-use a resistor
Same as technique one, expect use a 100 ohm 10 watt ceramic power resistor from Radio Shack pack of 2 was about $1.99. I covered all the wiring and resistor with shrink wrap. Advantage is no light and very little heat from the resistor. I also think the resistor has a very long life. It worked for me. From other postings, other resistor values may work as well.

Plug and play with connectors
After I decided to go with the resistor technique, I decided to make it plug and play with no wire cutting or tap-on connections. I acquired two male and female 9006 plug connectors and made up two plug and play watertight connectors that make up an in-series or in-line connection from the headlight plug/connector to the HID wiring. You can purchase plug connectors from http://www.autolumination.com/. They sell all sorts of automotive and home related lighting products.

My solder connections are a bit messy as I found it difficult to mechanically connect solid wire of the resistors to twisted strand wire. After insulation with shrink wrap and RTV silicon and 3m rubber insulation tape I covered the entire wiring package in shrink wrap to further insulate and hide my ugly solder work.

Not sure this offers much more detail on the how-to than others have posted, but it should be helpful for those who want to fix the low beam error on their own. It works for me on my e34.

added photos 11/1/08

11-01-2008, 12:38 PM
added three photos