Looking for help with DRL/Low Beam. (new owner).

[bez_ucha]

Hello,

I just purchased (picked it up yesterday) 2006 M3 HB. I think, this is GX model. (very basic one). While driving it home, I noticed that the low beams are very ineffective - it appeared to me that they were stuck in DRL mode. I have projector low beam with separate high beam reflector. Now, I tried searching, but I could not find conclusive answers to the following and I was hoping someone could help me:

1. I thought that DRL use high beam reflector, but supply lower voltage - is this true for all models or there are some models that use low beam projector as DRLs.
2. If low beam projectors are used for DRL - does the voltage drops or there is no difference between DRL and low beam?
3. If the voltage drops for DRL - what is the value?

4. Besides checking voltage - is there anything else I can check? (I am somewhat technical inclined)

Thank you so much,

Bez.

[Noisy Crow]

2007+ put the high-beams in series for DRL
2004-2005 DRL runs the low-beams at a lower average voltage via pulsing them on and off
2006.... I can't recall. 2006 was a transition year, so some things are like the 2007s and some things like the 2005s

Turn the lights off and see which set light up.... go from there.

[McGuyver_3]

04-06 had low beams as DRL's
07-09 had highbeam as DRL with reduced voltage

Technically the reduced voltage is a very fast pulse. It should run 6V, but with a volt meter you will only see 12V. A regular volt meter is not fast enough to see it unlike a scope. But the scopes can be big money and unless you use them every day, not a necessity.
While using low beams, voltage stabilizes to 12V. Your bulbs COULD be very likely not installed correctly. This seems to be a very common issue with these bulbs. Make sure the spacers and installation are correct. This could be your issue. Not so common but I have seen it a few times, the headlights start to haze over from ware and tear. An old set of headlights I had, I wet sanded them with 1000, 1500, and 2000grit sand paper and had a high power buff/polish done. Headlights were clear as new afterwards

[morganc]

Actually, the pulses happen at the same speed, but the duty cycle of the on portion of the wave changes. Basic principles of PWM, it changes the effective RMS voltage to the lights.

[bez_ucha]

Folks,

I want to thank all of you for the input. Of course the issue was with installation: based on your input I thought they may be rotated. However, some "skilled technician" did not even secure the clips! Upon initial inspection I removed the entire bulb with the adapter without much fuss. Now, the light bulbs are properly aligned and secured and I have much more light on the road. BTW, as indicated here: my 2006 used low beam DRL, but it does not appear to vary duty cycle ("voltage drop"). So in other words the light output is the same all the time, which - considering the age of the vehicle - is fine with me.

Thanks again,

Bez.