[NiNeTyOne]

I have one headlight that is intermittently switching off (beam malfunction), however it comes back on and will run (at times) for hours without issue after some time.

I'm wondering if anyone else has had this issue, and if it may just be a failing ballast?

[CaddymanLNL]

take the bulb out and inspect the ring that it plugs into for any burnt plastic or corrosion.

[NiNeTyOne]

Originally Posted by CaddymanLNL

take the bulb out and inspect the ring that it plugs into for any burnt plastic or corrosion.

Will do. Can I assume this has to do with the ground? I didn't notice any issues when the new bulbs went in last summer, and I'm in a very low corrosion area, but it's possible.

I'll check and report back.

[CaddymanLNL]

My only experience with a light not working in a headlight was the turn signal bulb in my 08 328xi touring. Replaced bulb, didn't work, dealer said the headlight was bad and replaced it, all good, under warranty.

Cool thing is they gave me the old (bad) headlight. I looked at it and you can see inside the ring that the bulb socket plugs into it was slightly melted and the metal tab that connects to the socket was buggered up.

So yeah, a quick visual check would at least eliminate 1 possible issue.

[NiNeTyOne]

Sockets are all good. Thing on the HID bilbs is they make no contact with the base that's metal, the +/- are on the bulb socket, so with the HID, it's not going to be the socket.

Still suspecting the ballast, possibly the control module, but those are very reliable in my experience.

[TemjinX2]

if you already swapped the bulbs, i would check the connectors make sure nothing is bent and the connectors are securely on the bulbs.

But more then likely your probably right its the ballast, if BMW still using the bosch ballasts, there trash.

i would just try buying a used one on ebay.

[Nate_1]

I have a similar issue, on a recently purchased 06 325i with xenon headlights. I'm new to the forums, and can't seem to make this in my own post, but the driver's side low beam spontaneously cuts off after 5-15 minutes of driving.

My uncle owned an E46 and told me to replace the tail light bulbs on that side, that the resistance can get thrown off even if the bulbs aren't blown.

Well, upon changing the running light tail-light bulb first, and as I pulled it out the two bulbs below it came on slightly dim... weird...

Well I looked up and the driver low beam had actually come on = so I fixed it right? NOPE.

I got in and had the warning light for "Lighting system failure" , but both low beams were working ... because logic...


So after turning it off in frustration and then deciding to start it up again, the warning light was gone and I had both headlights. I then went to drive a couple miles to see how long they would last, and then both low beams were out by the time I got out of the driveway... Fantastic...

I continued my drive annoyed, but realized when I got back that they were both on again! (it was dusk and not dark enough to tell yet) So at this point I'm really confused but happy, and when I went to drive the couple hour journey home from thanksgiving that evening, the driver one went out while I was loading the car... so it would appear no progress was made.

On my way out I grabbed a couple more 7506 bulbs and threw them into the remaining two slots in the tail light socket (I never replaced any bulbs in the trunk socket, they did all work). However, the driver's side still went out after it ran for a few minutes. THEN, as I got on the highway the driver's side came on! Buuuuut not without the "Lighting system failure" light. I drove the whole way with that light on.

Days later, it come on and off at different times, but always clears when I turn off and turn the car back on.


I have no idea what to do, except maybe change out the bulbs of the trunk lights (2x7506 and one reverse light which is like H21W at O'reileys). Many different posts have SIMILAR symptoms but something has been off about each one so I'm worried my situation is an odd ball.


Any help would be appreciated!

[Adieu]

You can get a cheapo chinese penny balast on amazon and try swapping it over. If it helps, that was the ballast.

Ditto with the bulb.

[NiNeTyOne]

Originally Posted by Adieu

You can get a cheapo chinese penny balast on amazon and try swapping it over. If it helps, that was the ballast.

Ditto with the bulb.

For what it's worth, it was the ballast. Swapped in a new one, problem solved. Thanks all for the input.

[Nate_1]

Originally Posted by Nate_1

I have a similar issue, on a recently purchased 06 325i with xenon headlights. I'm new to the forums, and can't seem to make this in my own post, but the driver's side low beam spontaneously cuts off after 5-15 minutes of driving.

My uncle owned an E46 and told me to replace the tail light bulbs on that side, that the resistance can get thrown off even if the bulbs aren't blown.

Well, upon changing the running light tail-light bulb first, and as I pulled it out the two bulbs below it came on slightly dim... weird...

Well I looked up and the driver low beam had actually come on = so I fixed it right? NOPE.

I got in and had the warning light for "Lighting system failure" , but both low beams were working ... because logic...


So after turning it off in frustration and then deciding to start it up again, the warning light was gone and I had both headlights. I then went to drive a couple miles to see how long they would last, and then both low beams were out by the time I got out of the driveway... Fantastic...

I continued my drive annoyed, but realized when I got back that they were both on again! (it was dusk and not dark enough to tell yet) So at this point I'm really confused but happy, and when I went to drive the couple hour journey home from thanksgiving that evening, the driver one went out while I was loading the car... so it would appear no progress was made.

On my way out I grabbed a couple more 7506 bulbs and threw them into the remaining two slots in the tail light socket (I never replaced any bulbs in the trunk socket, they did all work). However, the driver's side still went out after it ran for a few minutes. THEN, as I got on the highway the driver's side came on! Buuuuut not without the "Lighting system failure" light. I drove the whole way with that light on.

Days later, it come on and off at different times, but always clears when I turn off and turn the car back on.


I have no idea what to do, except maybe change out the bulbs of the trunk lights (2x7506 and one reverse light which is like H21W at O'reileys). Many different posts have SIMILAR symptoms but something has been off about each one so I'm worried my situation is an odd ball.


Any help would be appreciated!

I ended up going to the dealer for a diagnostic... After I tore the entire front end apart to replace a ballast and discovered that I had some aftermarket headlights and ballasts (well done and clean I might add)

Turns out, the "FRM module" was bad. I could have them do it for ~$900 or buy the part for like ~$450 and try and do it myself or bring it to them and it would total about 800... not sure how that logic works!

Anyway, that was the conclusion.