I can't find any bulbs that do not light as they should, but I still see the bulb warning light...

My OBDII scanner doesn't see any codes. I did have a fog light that was burnt out but it has been replaced. Been this way for a couple weeks now...

Any ideas? I didn't check interior bulbs, could one of them set the light?

 

I have an '09 with identical complaints, and this has been covered many times on various threads. Since I am (relatively) new to the forum, I will answer anyway - -

The FRM (assuming R56) has current shunts that feed each exterior light. The voltage drop across the current shunt is directly proportional to the current feeding each individual lamp. I believe there are 22 of them for a standard configured mini - yes - that many individual channels, more / less depending on marker lights, fog lights, etc.
When the car is started, the FRM pulses each lamp individually - an extremely fast pulse - not enough to actually light the lamp, but enough to get a reading across the current shunt.
If the voltage drop measured on the shunt does not match the FRM's expectation - you get a lamp warning.

Now - lets say you have a bulb which has grown some crud on the positive contact - it is highly ohmic - i.e. gives a higher resistance than a virgin contact - the total resistance for that bulb's channel can actually cause the current to be lower than spec even though you visibly see the lamp on, and you still have a light.

Here are some other causes:
1) Someone has installed LED lamps without dropping resistors - so the current is too low
2) Lamp filament is damaged / old, and is drawing low current even though the lamp is on
3) Lamp housing has corroded - i.e ground or positive contacts have oxidized and you have a higher resistance, even though the lamp is on
4) FRM module is faulty (very, very rare)
5) Bad wiring harness or crimped connector at the bulb end
(I have personally experienced all of the above 5, 4 of them on my last R53!)

You need a proper code reader - BMW style / INPA or ISTA-D software to be able to show specific faults from the FRM or appropriate module which will highlight the specific lamp or lamps that is causing the error so you can diagnose. If there is a way to do it through hidden menus, I hope someone posts as I have never found one.

I find that removing and replacing the error lamp does not always clear the error - especially with fog lamps or tail lights which have some exposure to rain / the elements. I chased my tail on my '07 R56 S for awhile until I realized the bulb socket in the second parking light brake bulb were bent and only making partial contact! New bulb, cleaned the contacts, etc. did nothing until the mechanical issue was resolved. I am chasing a wiring fault on my '09 R56 base where both of the top parking/brake lamps will not light - new bulbs, replaced the sockets - its in the harness somewhere between the FRM and rear of the car! pita....

Hope that helps!