One tail-light is brighter than the other

[jsoto]

12V is 12 volt right ?

One side of my tail-light is brighter than the other.

I swapped bulbs, etc with no difference

Note: my LCM went south and the my tails were on for a good 24 hrs....(basically all tails and the 3rd brake light)
LCM was replaced. All the funky things went away, except I just noticed the brightness difference on the tail lights

For example, on one side, it is nice and bright. When I flip it to the other, it is dimmer.

[Ricky Bobby]

are you sure you dont have a problem with the taillight socket having a poor connection? this is a common problem area with e53 the heat from the bulb socket makes poor contact with the circuit board, causing the light to be dimmer and eventually you will get a bulb out warning from it.

[TerminatorX5]

the 12 VDC is not the 12VDC in the BMW world... BMW is using so-called PWM in its LCMs, Pulse Wave Modulation, where the full 12 VDC is applied to circuitry in waves of 12V-0V-12V-0V, thus effectively reducing the illumination of the halogen light... if you connect an LCD light to the same circuit, you will see rapid flashing of the LCD as the response time of the LCD is much-much faster then a halogen light... If one light is really dimmer than the other, it might have too much of the PWM signal (wider gaps of 0V, dimmer the light)...

Since I do not know why the light will do one side in PWM and not the other side (or, apply different values of PWMs) we need to make sure that this is a really case of the PWM applied to your lights...

do you have 12V leds floating around, that you could have connected to the light, for the test purposes?

[jsoto]

The turn signal is nice and bright.
It's both the brake and the *bottom* bulb that is dimmer.
I've yet to take the tailight out to look at the circuit board but if I recall it was either all or nothing...when the contact/weld came loose

[jsoto]

I wish I did on the LEDS right now to test
I actually bough those LED bulbs awhile back - did not like the output at all

[Ricky Bobby]

if its the brake and bottom bulb dimmer i am leaning towards you having a circuit board problem.

if i recall correctly there are just 3 or 4 8mm bolts holding the taillight on can you pop it off and check?

[jsoto]

I don't know what the fix was as it's fixed......
My Indy who replaced the LCM - told me it needed a wiring hardness repair and a tail harness (note - I did not take out the tail prior to check out the circuit board prior to dropoff). Surprisingly, I pick it up and the tails are just fine.

I have not seen the X in a couple days, but will see it Saturday. I'm sure it's still working just fine now.

Strange eh.

[Ricky Bobby]

i'm pretty sure your indy who did the LCM meant this, and yes your tails will come and go, sometimes they will be out and sometimes they won't because its such an intermittent connection at the circuit board, check out this thread for details:

http://www.xoutpost.com/bmw-sav-foru...light-fix.html

[jsoto]

No....I don't think so...
I'll extrapolate more.

There has never been a loss of power - aka circuit board on pre or post LCM repair. Just the fact that one side was about 40% dimmer than the other. If it was the bad connection, IMO, there should have been at least 1X where there was power to the lights...


I'd hate to say it, but I do feel that that wire harness repair was more a upsell....I was advised it was burning/corroded/melting on the so called problamatic left side.
He did a wire harness repair on the right side, and when I looked post, I did not see a damm thing done as far as I could see. My Indys been good but lately I've had to question some of the stuff I've been advised to repair....

[TerminatorX5]

not that it matters now, but switching power feeding pins from LCM to the tails (left pin to send power to right tail, and the right pin to send power to left tail) would have given an idea if the issue was stationary to the tails or portable with the switch... from that point, you would have narrowed down your further options...