2004 4.8iS Headlight ALC Module Question

[BimmerE38E53]

Originally Posted by crystalworks

Okay, after doing some more reading. LOL, most of the answers were in this thread ironically. I am not sure why I don't have leveling in my driver's light. Going to use a multimeter to verify the AHL is sending signals to the light. If I do get signals to the light... then I will switch the driver's side back to the passenger side to see if it goes through the leveling procedure upon startup. If it doesn't, then I know the problem is either the used LCM module I put on, or the stepper motors inside the headlight being damaged somehow.

Uggggghhhhhh... I'm wondering if the LCM disables the light due to the fault with the adaptive light system... whether it be the ALC or the AHL??? Man do I ever need to get DIS and the other diagnostics software working...

Update: Checked pins 9 and 10 on the headlight connector which come from the AHL to the ALC and have +12v constant on 10 and +12v on activation of the headlights (auto) on pin 9. That leads me to believe the AHL is doing what it is supposed to do. So... I can cross that module off the list.

This leads me to believe that the problem is either the new (used) ALC module I put on this headlight... or the problem is internal and when the ALC module shorted it took out the stepper motor(s) in the headlight. So once again the bumper has to come off. LOL The universe is not going to be happy until those clips on the side of the fenders are broken apparently.

And I believe you are correct in the location.

This is the fault that I am still getting. The ALC is the module under the headlight. And it is not at fault. I have replaced with brand new and the old one. Both work. The fact that the LCM is giving the fault leads me to believe it's either internal in the LCM or the AHL. Not good at running down electrical checks though so I'm not really sure.

[crystalworks]

Originally Posted by BimmerE38E53

And I believe you are correct in the location.

This is the fault that I am still getting. The ALC is the module under the headlight. And it is not at fault. I have replaced with brand new and the old one. Both work. The fact that the LCM is giving the fault leads me to believe it's either internal in the LCM or the AHL. Not good at running down electrical checks though so I'm not really sure.

Check at the headlight harness for voltage on the two signal wires form the AHL. If you have voltage (like I do) the problem is not likely to be in the AHL. Especially if you are getting the same readings from both the driver's and passenger's sides. I'm betting that there has been damage in the headlight itself, to the stepper motors. Or perhaps there is corrosion on a pin contact or something like that. I'll check it out next time I have a chance to pull the bumper.

And nope, I could never go back to those poor excuses for OEM halos. My buddy, who is very into BMW's and has done many halo installs/retrofits, still marvels at the X5's new halo retrofit and says they are the best looking ones he's seen. Makes me smile every time I am walking to, or from, the X.

Edit: If you wanted to ditch the jumper wire you have. From the reading I've done, since you have the software suite running, you could code out headlight leveling error checking and the LCM would re-activate your low beam that is out. It is disabling voltage to the low beam/LCM/etc as a result of the fault in the LCM. I'm guessing this is just to notify the owner of a fault, since the leveling is not something everyone would notice a fault with. Stupid design if you ask me... but hey, that's what you put up with when you love the way BMW's drive.