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Discussion Starter · #1 · (Edited)
Hi Guys,

Just today, the Xenon headlights on my 2001 330i started flickering. Here are the details:

SYMPTOMS:

1.) When I turn my lights on, the Xenons flicker at about the same pace as a signal lights.

2.) As the Xenons flicker, I can hear a clicking sound coming from the glove box at the exact same tempo of the flicker. It sounds like a relay.

3.) If I turn off the Xenons and simply go to parking lights, the clicking in the glovebox stops and there are no flickering issues with the non-Xenon parking lights.

4.) With the parking lights on, I can turn my fog lights on. Upon doing so, the same clicking (at the same tempo) comes out of the glovebox area. Although there is a clicking sound, the foglights do not flicker and seem to be working fine. As soon as I turn off the foglights, the clicking from the glovebox stops.

5.) Interestingly, if I turn on a signal light or the hazard lights, then the Xenons stop flickering. As soon as I turn off the signal light, then the Xenons start to flicker again.

6.) Every now and then over the last month, both of my "taillight out" warning lights would appear at the same time, even though the taillights working perfectly fine. Recently, the warning lights have been coming on more often. I have read that this issue may be related.

ATTEMPTED RESOLUTIONS:

1.) I went through the process of re-grounding both of my tailights (as per the instructions of another member), but nothing has changed -- I still have flickering headlights and my "taillight out" indicator bulbs are still illuminated. Surprisingly, none of the pins on the wiring clip appeared to be burned out.

2.) I tried swapping both of the taillight bulb holders from a friend's E46. The "bulb out" warnings were still on the dash, and the flickering headlight problem persists. I tried my taillight bulb holder's in my friends car and they worked without a problem.

3.) I tried unplugging both taillights, but the problems persists.

4.) I tried unplugging both the Xenon headlights but the problem persists (because I can still hear the clicking from the glovebox).

5.) I tried swapping the Xenon bulbs, and the problem persists.

Any help is GREATLY appreciated!

Thanks!
 

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Discussion Starter · #3 · (Edited)
Sounds like a bad ground to me. Check the wiring for your taillight. I betcha one of the pins will appear to be burnt
Thanks for the suggestion, but please refer to Attempted Resolution #1 above. I thought that a bad ground in the taillight was the issue as well, so I spliced in a new ground wire for each taillight. I.e. I spliced into the brown wire about an inch above the taillight wiring clip, and ran a new wire directly to a ground on the taillight's metal "wiring" board.
 

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Thanks for the suggestion, but please refer to Attempted Resolution #1 above. I thought that a bad ground in the taillight was the issue as well, so I spliced in a new ground wire for each taillight. I.e. I spliced into the brown wire about an inch above the taillight wiring clip, and ran a new wire directly to a ground on the taillight's metal "wiring" board.
Try unplugging one headlight at a time to see if the flashing stops. It could be a ballast is going bad for the xenon. If both of the lights/ballast turn out to be good, then off you go to the junk yard or the dealer for the light module.
 

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Thanks for the suggestion, but please refer to Attempted Resolution #1 above. I thought that a bad ground in the taillight was the issue as well, so I spliced in a new ground wire for each taillight. I.e. I spliced into the brown wire about an inch above the taillight wiring clip, and ran a new wire directly to a ground on the taillight's metal "wiring" board.
Coulda sworn that wasn't there last night? I swear I'm going nuts (not to be confused with the member goingnuts..)

Are the xenons factory, or did you retrofit them at some point? If retrofitted, what method did you use to avoid the errors - LCM reflash, cancellers, or pulling the fuse?
 

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Noone Special
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Coulda sworn that wasn't there last night? I swear I'm going nuts (not to be confused with the member goingnuts..)

Are the xenons factory, or did you retrofit them at some point? If retrofitted, what method did you use to avoid the errors - LCM reflash, cancellers, or pulling the fuse?
Wow, good call. never crossed my mind that they could be aftermarket.
 

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One of my xenon was flickering too and took the bulb off and the filament was broken, changed the bulb and problem fixed...
 

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Discussion Starter · #8 ·
Coulda sworn that wasn't there last night? I swear I'm going nuts (not to be confused with the member goingnuts..)

Are the xenons factory, or did you retrofit them at some point? If retrofitted, what method did you use to avoid the errors - LCM reflash, cancellers, or pulling the fuse?
It was there last night, but I had it listed a "#7". I rearranged my post a little bit so that it is easier to separate the symptoms from my attempted resolutions.
 

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Discussion Starter · #9 · (Edited)
The headlights are original -- there was no aftermarket conversion done. The headlight on the right side has always been a different colour (less blue) than the left side. I've tried swapping the bulbs left and right but the right side remained less blue. I'm not sure if this is related or not. Also, today I had my battery die when doing some testing (about five minutes), but that could be because I was playing around with my lights a lot last night without the car running (and the flickering on/off of the Xenons is probably a huge power draw).

It may be related, but every once in a while my right-side Xenon won't come on. It used to flicker every once in a while when going over bumps. Perhaps I have a bad bulb -- I will take a look.

Thanks!
 

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Can you try swapping LCMs with your friend's car?

For your xenon issue... being 10 years old, it's certainly possible that the bulbs are dying. Xenons do tend to flicker when they're very near death. A bad ignitor would also cause flickering though.
 

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Clicking from the glovebox area...you say it may be a relay. So, does anyone know if there's a relay in there he can check? Maybe swap it temporarily with another relay for diagnostic purposes?
 

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Discussion Starter · #13 ·
Can you try swapping LCMs with your friend's car?

For your xenon issue... being 10 years old, it's certainly possible that the bulbs are dying. Xenons do tend to flicker when they're very near death. A bad ignitor would also cause flickering though.
I was only visiting my friend for the weekend :(

I tried swapping the bulbs with some other Xenons that I had lying around, but no luck. I even tried unplugging both bulbs but the clicking from the glovebox persisted.
 

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Clicking from the glovebox area...you say it may be a relay. So, does anyone know if there's a relay in there he can check? Maybe swap it temporarily with another relay for diagnostic purposes?
There's a foglight relay over there, but as far as I knew, the other lights are powered directly by the LCM.
 

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Discussion Starter · #15 ·
Clicking from the glovebox area...you say it may be a relay. So, does anyone know if there's a relay in there he can check? Maybe swap it temporarily with another relay for diagnostic purposes?
There is a clicking sound (VERY much like a relay) coming from the glovebox when I have the foglights turned on. The clicking sound is the exact same tempo as the flickering headlights. If the foglights are off, there is no clicking sound (but the Xenons continue to flicker).

When I pulled out the taillights to have a closer look, I noticed that the taillight bulbs were dimming a tiny bit each time the glove box clicked.

Are there relays behind the glove box that may be related?
 

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Discussion Starter · #16 ·
There's a foglight relay over there, but as far as I knew, the other lights are powered directly by the LCM.
I find it interesting that I only hear the clicking sound from the glove box when I have the fog lights on. The clicking sound must be the fog light relay going crazy if you say the fog light relay is behind the glove box. I suspect there is also a signal light relay in there? The signal lights are somehow related, because the problem goes away when I'm signalling. These symptoms have to be related somehow.

Thanks!
 

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There is a clicking sound (VERY much like a relay) coming from the glovebox when I have the foglights turned on. The clicking sound is the exact same tempo as the flickering headlights. If the foglights are off, there is no clicking sound (but the Xenons continue to flicker).

When I pulled out the taillights to have a closer look, I noticed that the taillight bulbs were dimming a tiny bit each time the glove box clicked.

Are there relays behind the glove box that may be related?
Only one I know of is the foglight relay... but maybe it's just another sideeffect rather than the cause of a problem? I am starting to think your LCM is failing. Really would be good to find another E46 (with HIDs) that you can temporarily swap LCMs with
 

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Discussion Starter · #18 ·
Only one I know of is the foglight relay... but maybe it's just another sideeffect rather than the cause of a problem? I am starting to think your LCM is failing. Really would be good to find another E46 (with HIDs) that you can temporarily swap LCMs with
I think you are correct -- I think these are all symptoms. The more I read, the more I think it is a bad LCM (causing the clicking of the Fog Light relay, the flickering to stop when I use my signals, the "bulb out" warnings in the rear, etc.) The common denominator is that all of these are controlled by the LCM. I found the following description of the LCM functions:

Extract from BMW WDS info about the Light Switch Module.

Light switch centre (LSZ)
In addition to the electronic control and monitoring system for the external vehicle lights, the light switch centre also comprises the switch for sidelights/dipped beam, the pushbuttons for fog lights and rear fog lights as well as the potentiometers for instrument locator lighting and manual headlight vertical aim control.

Scope of functions of light switching centre
Control and monitoring of the outer headlights and lamps, including the indicator and hazard warning flasher function

Control of relay for fog lights

Evaluation of load sensors for automatic headlight vertical aim control and the resulting activation of stepper motors of evaluation of potentiometer for manual headlight vertical aim control.

Dimmer function for instrument and locator lighting (terminal 58g) as well as the function and locator lighting for the hazard warning switch.

Communication with other control units and diagnosis takes place via the K-bus. The light switching centre receives information via this bus relating to the vehicle status and also provides information on the status of the controlled lamps (defective/OK, switched ON/OFF).

The indicator lamps for full beam, fog light, rear fog light and direction indicators in the instrument cluster are controlled by the light switching centre on the basis of K-bus telegrams.

Design
The light switch centre consists of a control unit and operating panel
Both units are interconnected by means of a plug connector.

Control unit
The control electronics is accommodated in the control unit.

Operating panel
The switches for sidelights/dipped beam, fog lights/rear fog lights as well as the dimmer for headlight vertical aim control and instrument lighting are integrated in the operating panel.

The operating panel can be replaced separately from the control unit.

If replacement is necessary, corresponding reference to this is made in the test module.

Lamp monitoring
The lamps are monitored in OFF and ON status.

Cold monitoring in the OFF status takes place by briefly switching on the lamp (so short that the lamp does not light up). The lamp current is monitored and an assessment is made as to whether the lamp is defective or not.

Note

If the battery voltage drops below approx. 9.5 V, the lamp status can no longer be monitored or output.

Activating indicator lamps in the instrument cluster
The indicator lamps for left direction indicator, right direction indicator, rear fog lights, fog lights, full beam as well as the LEDs in the pictogram incorporated in the instrument cluster are activated via the K-bus.

Emergency mode
Independent hardware is provided in order to maintain the functions necessary for driving safety in the event of the control unit failing.

If the light switching centre is in emergency mode,

Tail lights and dipped beam lights are switched on at terminal 15 irrespective of the position of the corresponding light switch

Left and right brake lights are switched on at terminal 15 and the brake light switch operated

Direction indicators, hazard warning lights, full beam, headlight flasher, fog lights and rear fog lights cannot be switched on.

Diagnosis is not possible

If in emergency mode, the light switching centre must be replaced.
There are lots of cheap LCMs for sale on eBay (about $60), but I think they have to be programmed to your car. I already have an appointment at BMW for next week, and they will probably want significantly more for the LCM . . . perhaps $400 :( I wonder if they would install and reprogram a used part?

Thanks!
 

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I think you are correct -- I think these are all symptoms. The more I read, the more I think it is a bad LCM (causing the clicking of the Fog Light relay, the flickering to stop when I use my signals, the "bulb out" warnings in the rear, etc.) The common denominator is that all of these are controlled by the LCM. I found the following description of the LCM functions:

There are lots of cheap LCMs for sale on eBay (about $60), but I think they have to be programmed to your car. I already have an appointment at BMW for next week, and they will probably want significantly more for the LCM . . . perhaps $400 :( I wonder if they would install and reprogram a used part?

Thanks!
Dealers can't recode used LCMs (even if they wanted to, their tools simply won't allow it). I sent you a PM
 

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Interesting that the info you found said that if battery voltage goes below 9.5v, lamp status may be affected. You also mentioned that your battery went dead while testing. Have you tried swapping your battery with one that you know to be good? I think TerraPhantm has your problem nailed, but it would be good to absolutely rule out the battery. I have seen more weird problems solved on modern cars by replacing the battery than I ever thought possible. I have also seen relays "flutter" ( the rapid clicking you heard) from insufficient pull in voltage. Just a thought, and a guess.
 
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