e92 LCI inner tail light issue

davidzh · 08-22-2025, 08:40 PM

Hi,

I know this topic has been discussed a few times, but what happened to my e92 LCI inner tail light is very weird,

The passenger side inner tail light stopped working; and I got error code A8BF. I thought it could be burnt out so I bought a used one to replace it. However the used one didn't work either.

So I took some time to measure the pinout of the inner tail lights.

Here is what I got:
The failed one (passenger side)
Pin1 Yellow brown
Pin2 Brown
Pin3 Gree red

Between pin1 and pin2 is 12V
Between pin1 and pin3 is 4.5-5V (I guess it is the root cause?)

The normal one (driver side)
Pin1 Yellow green
Pin2 Brown
Pin3 Yellow black

Only between pin1 and pin2 is 12V

I believe brown is the ground.

I switched the lights:
I connected the passenger side lights to driver side (I tried mine and the used on that I bought online)
I connected the driver side light to passenger side
Neither of them lighted the LED
Both of them lighted the H21W reverse light (which is disabled by default in North America)

I planned to:
1. buy a brand new passenger side inner light to have another try
2. Leave it to a professional garage to handle

I only got the error code A8BF. There was no short-circuit light in the bimmerlink.

Do you have any ideas? Could be a malfunction FRM?

ptpending · 08-23-2025, 04:05 AM

why don't you want to check wiring from light to frm
especially in grommet from door to body ?

davidzh · 08-23-2025, 07:12 PM

Quote:

Originally Posted by ptpending

why don't you want to check wiring from light to frm
especially in grommet from door to body ?

You may be right.

I used a DC power to test them. For the driver side, when I supplied 12v between pin1 and pin2, the H21W reverse light was lighted, when I supplied 5v between pin3 and pin2(ground), the led was lighted. Both my old one and the one bought from facebook market couldn't be lighted. I guess I was screwed.

davidzh · 09-05-2025, 12:09 PM

Back to my post, I replaced the inner tail assembly and the issue was addressed. So the voltage of pinouts is correct, 4.5-5V pin1 and pin3 is to detect the assembly, however the driver side doesn't have this signal.

08-22-2025, 08:40 PM	#1
davidzh Registered 0 Rep 4 Posts Drives: E92 Join Date: Jul 2025 Location: Canada iTrader: (0)	e92 LCI inner tail light issue Hi, I know this topic has been discussed a few times, but what happened to my e92 LCI inner tail light is very weird, The passenger side inner tail light stopped working; and I got error code A8BF. I thought it could be burnt out so I bought a used one to replace it. However the used one didn't work either. So I took some time to measure the pinout of the inner tail lights. Here is what I got: The failed one (passenger side) Pin1 Yellow brown Pin2 Brown Pin3 Gree red Between pin1 and pin2 is 12V Between pin1 and pin3 is 4.5-5V (I guess it is the root cause?) The normal one (driver side) Pin1 Yellow green Pin2 Brown Pin3 Yellow black Only between pin1 and pin2 is 12V I believe brown is the ground. I switched the lights: I connected the passenger side lights to driver side (I tried mine and the used on that I bought online) I connected the driver side light to passenger side Neither of them lighted the LED Both of them lighted the H21W reverse light (which is disabled by default in North America) I planned to: 1. buy a brand new passenger side inner light to have another try 2. Leave it to a professional garage to handle I only got the error code A8BF. There was no short-circuit light in the bimmerlink. Do you have any ideas? Could be a malfunction FRM?
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08-23-2025, 04:05 AM	#2
ptpending Brigadier General 805 Rep 3,566 Posts Drives: e81 Join Date: Dec 2013 Location: Poland iTrader: (1)	why don't you want to check wiring from light to frm especially in grommet from door to body ? __________________ E81 2007 130i 6cylinder Montego blue Retrofits: Harman Kardon, High-beam assistant, Removable tow hitch. Auto-dim folding exterior mirrors. Lumbar support. Perfomance Brakes.
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09-05-2025, 12:09 PM	#4
davidzh Registered 0 Rep 4 Posts Drives: E92 Join Date: Jul 2025 Location: Canada iTrader: (0)	Back to my post, I replaced the inner tail assembly and the issue was addressed. So the voltage of pinouts is correct, 4.5-5V pin1 and pin3 is to detect the assembly, however the driver side doesn't have this signal.
	Appreciate 0 Quote