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2001 330i (5-speed)
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Discussion Starter · #1 · (Edited)
Driving at night.
Every few seconds, the headlights turn off for a split second, but come back on.

What may be the culprits?
Doubt its the bulbs or ballasts since its both sides.
Headlight switch?

UPDATE:
Finished the tail light ground splice today.
Let's see if this fixes the headlight issue.

To recap:
E46 headlights were flicking / turning on and off repeatedly.
Scary.

I noticed tail light was dim and flickering.

I read that the taillight ground wire gets corroded in the connector. High resistance.

Flickering lights is a sign of a bad ground, usually in the tail lights.
It causes the light control module to keep resetting itself, and this causes the headlights to flicker.


So, to bypass the corroded wire connector, I spliced the ground and directly connected it to the bulb tray ground path.

  1. Yellow quick splice connector onto the brown ground
  2. Pinch blue wire into yellow butt cap. Would not stay snug, if yanked, so I reinforced in place with duct tape.
  3. Self tapping screw drilled directly into ground path of bulb tray. Tightened it over the blue wire.
Once I added the additional ground path, the bulb lit up way brighter.
Hopefully this solves the headlight issue.


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2001 330i (5-speed)
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Discussion Starter · #2 ·
Can someone help me figure out the difference between the ignitor and the ballast ? Anyone have pictures?
 

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2016 340i xD 6-spd
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Maybe monitor your voltage when you're driving...if it goes up and down, there you go. I'd start looking at the battery and your electric system...maybe push in all your fuses, too?

Good luck, Buddy!
 

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2001 330i (5-speed)
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Discussion Starter · #4 · (Edited)
Maybe monitor your voltage when you're driving...if it goes up and down, there you go. I'd start looking at the battery and your electric system...maybe push in all your fuses, too?
No, it is not such a vague issue, and actually turns out to be a very commonly documented issue with E46
Common culprits are brittle wiring in the headlight system and/or a taillight ground.

 

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There's a removable cap on the top of the headlight housing that you can use to change the xenon bulb and or inspect the internal wiring. The wiring insulation is known to break off and cause flickering issues. I used liquid tape on my damaged wiring and no problems since.
 

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Super Moderator
'03 325iT Mystic Blau
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5,742 Posts
No, it is not such a vague issue, and actually turns out to be a very commonly documented issue with E46
Common culprits are brittle wiring in the headlight system and/or a taillight ground.

It's far more common on the coupes and verts than sedans and wagons because the dynamic xenons have much more movement leading to work hardening and breaks of the wires.
 

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2001 330i (5-speed)
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Discussion Starter · #9 ·
Automotive tire Motor vehicle Hood Automotive lighting Bumper


Noticed the driver’s taillight was weak and flickering.
Swapped bulbs and still weak.
Might be a ground issue here.

Spent a literal hour trying to detach this clip (to hopefully clean corroded contact)
Gave up after an hour. Tried screwdrivers, pliers, picks, prying.
Plastic pigtail started to crumble, yet was firmly lodged in place.

Wiring clips easily the #1 nightmare in car DIY.
What are my options? Cut off the wires and buy a new pigtail harness?
 

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2001 330i (5-speed)
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Discussion Starter · #11 ·
Sounds like the assembly is toast. If you’re unable to free the connector, the only option would be to cut it off and solder on a new donor pigtail.
How do I get a new pigtail ? Closest salvage yard is 5 hours, another state.
 

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3,696 Posts
The only way that halogens would have been brighter is if your reflector bowls were burnt.
I dunno about that. We have one of each, and while more lumens come out of my gas discharge
lights, the wagon's halogens work far better at lighting up the road, both in low and high beam.

The catch, of course, is that the D2S's are Federal from pre- 2002, and the halogens
are post- 'reform' pattern. On top of that, I see better in the red spectrum than I do in
the blue, so the higher color temperature of the gas discharge lamps is wasted on my old eyes.

The ignitor generates the high- voltage pulse that the lamps need to strike.
The ballast runs the lamp while it's constantly burning. As I understand it, the ignitor
is the smaller plastic box attached directly to the lamp, while the ballast is
the larger aluminum fender- mounted box (usually under the lamp housing somewhere)
But I'm working from a general understanding of discharge lamps, as the E46 version on my
car has been working ok so far.

t
not bothered enough to change.
 

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2001 330i (5-speed)
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Discussion Starter · #15 ·
I removed the headlight to inspect the wires.
Turns out, I do not have any access holes like the one in the video.
Did they change styles at some point? This seems to be a dead end.
How can I inspect wires where they are not accessible ?

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Discussion Starter · #18 ·
Like I said earlier, that problem is far more common in coupes and verts, and as such the light in the video is a coupe/vert one. Your sedan light has the bulb access on the back, remove that and see what you can see.
I removed the rubber dome in the rear and saw no wires inside.
 

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'03 325iT Mystic Blau
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I removed the rubber dome in the rear and saw no wires inside.
Here's what's inside the AL xenon housing, behind the reflector -

Ignitor. Inside bottom of housing below low beam projector.


Wires exiting housing going to ballast, which can be seen through the opening for high beam bulb access.


Ballast on back of housing to left, wires visible through bulb openings.
 

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Discussion Starter · #20 ·
Thanks for pointing the way. You are a huge resource to this forum!
Let me try to remove bulbs and get a closer look
 
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