E90 inner tail light issue

[Alley-C]

So driving my e90 last week (Pre LCI 330d) and randomly it gives an error for the rear light not working, so when I got to my destination I checked and it was the right inner tail light which was not working. Like most people would think it was just a bulb which needs to be replaced so did I, unfortunately I don’t have time during the week to stop take out the bulb and go get a new one so I already planned to sort it out on the weekend.

However continuing into the week the error went away and the tail light was working again, so not thinking too much of it I was just happy it was working cause of a slight OCD tendency I can’t stand it when something small like that is not working, it literally plays in the back of my head that the light is not working and other people can see it too:hammerhead:

Moving further into the week on Thursday morning to be exact on my way to work the error popped up once again, when I got to work checked the tail light and the same inner light stopped working again, this time it hasn’t started working since.

Found some time on Sunday to have a look hoping it’s just a simple bulb change, but I was sadly wrong…:dunnoanymore:
Once I opened up the boot lid lining and pulled the bulb housing out I inspected the bulb and it seemed fine so to test it I took the bulb from the left inner which works fine and put it on the right inner which did not work on the right. Next in order to confirm if the housing is not the issue I tested the right sides housing on the left side and it working perfect.
So its not the bulb nor is it the housing, next I checked the fuses and both fuses for the light are good and no signs of any damage. Done a bit of googling and apparently it’s a common issue on these cars for the wires to break where the harness goes from the boot into the body in the rubber housing.
I pulled the rubber housing away hoping I find a broken wire and once again sadly I did not, disconnected the harness from the inner lights, number plate lights, boot lock and boot handle and pulled it all the way though the boot and inspected the whole harness as well as pull the harness in the boot itself and inspected the rest of the of it where it runs just under the back board. I could not find a single break in the wire. :skit:

After the heat from yesterday I gave up and just put everything back and now have this stupid inner tail light in the back of my mind since then.
Has anyone else had such an issue before or any advice on a way I can troubleshoot or try finding a break in the wire? Any advice would be appreciated.

 

[SubLoaded]

Yep. common E90 issue.

Something must be loose. Open you boot and give the inside of the trunk (the board) a slight knock. See if the light comes on (even just for a short span of time).

You may need to solder the connection (if you're not willing to buy a new light).

If you have subwoofers in the boot then that's quite likely why it broke in the first place, however I have noticed a lot of E90's with dead inner tail lights so yeah doubt everyone is rocking woofers :fencelook:

 

[Alley-C]

Yep. common E90 issue.

Something must be loose. Open you boot and give the inside of the trunk (the board) a slight knock. See if the light comes on (even just for a short span of time).

You may need to solder the connection (if you're not willing to buy a new light).

If you have subwoofers in the boot then that's quite likely why it broke in the first place, however I have noticed a lot of E90's with dead inner tail lights so yeah doubt everyone is rocking woofers :fencelook:

Thank you for the feedback @SubLoaded , I dont think buying a new light would resolve the problem because if i plug the left sides connector into the right side(which is not working) it then works fine, that whats leading me to suspect an issue with the wiring, i also tested the connector with a test light as well and its not receiving any power on the same wires the left side is receiving.

No subs in the boot however the boot shocks are worn out so it does it slammed a bit by people who dont know it unfortunately :dunnoanymore: i will be replacing those soon, (BMW replacement boot shocks R2200 for both from the stealers) and (Gold Wagon is R199 each)

 

[Nick]

Mine did it too, i cleaned the contacts on the housing and replaced the globe.
working now.

I think overtime the connection gets loose or dirty.

 

[KiLLRoYza]

Had this problem as well.

Bought two new inner housing things for both sides with new globes which sorted it.

Pretty inexpensive from Bemows

 

[Alley-C]

So I finally fixed my right inner tail light issue, after months of it annoying me :hammerhead:

just in case anyone else with an e90 has a similar issue I'm posting my solution here,

To start with I needed to make sure there was no break in the cable from the connector right through to the plug on the FRM module, just the thought of stripping the interior made me sick. Like Bill Gates once said if you want to find the easiest way to do something, hire a lazy person and they will find the easiest way to get the job done. and luckily I am quite lazy so the brain storming began and I realised I can use a multi meter to check for a break in the circuit without stripping much.

Pulled of the boot lid cover and pushed a wire into the connector to make contact with the wire for the tailight (yellow/with a purplish line) and ran the wire to the front of the car, I then pulled of the covers in the drivers footwell to reveal the FRM module and pulled the connectors out till I found the wire I was looking for.

Once if found the correct wire (yellow/with a purplish line) i did not want to cut the wire to test so I took a straight pin and pieced the wire through to make contact, I then put the multi meter on the lowest Ohm's setting. It then displays an "I" for infinity meaning there is no resistance as it is not a complete circuit. I then took one probe and held it on the wire I had running from the tail light connector and took the other probe and held it on the straight pin, the multi meter then showed resistance which indicated that there was no break in the wire from the FRM to the Tail light connector.:smilebounce: Saved myself a whole lot of work.

Now after a lot of research I found out that the FRM Module has a safety feature when it does its check cycles testing each bulb and it notices a short if the short is persistent for 50 check cycles it will shut off power in the circuit where the short was found. Even after repairing the short in the circuit which in my case was replacing the bulb as the back of the bulb was melted which caused the short still does not allow current back into the circuit.

This safety feature is basically to protect the car against fires in the event there is a short in the wiring harness which could set the car alight. Now comes the question of how do you actually get power back into the circuit again, start by checking which FRM you have in your car (Mine has an FRM2), You will then need a K-Dcan cable and the standard BMW tools software which has "Tools32" and you will be able to reset the Counter on the FRM for the particular circuit, I'm not going to do a step by step guide as if you google "How to reset FRM counter" you will find a number of DIY's.

Note this is not only for the tail light, everything controlled by the FRM has a counter which can be reset provided the short which caused the issue has been fixed. Hope this helps someone else in the future :thumbs: