The battery recently went dead in my mini. In a hurry and alone instead of pushing it out of the garage and rolling it off, I hooked up the charger and turned it on start. It buzzed a few times the needle jumped up and down and I quickly unhooked it.
The next day I replaced the battery, not realizing I needed to hook 12 volts to it, needless to say the passenger airbag light was on after the change, also the radio has not made a sound since.
I took it to the Mini Dealer. They said the passenger side air bag sensor was bad and the amp in the radio was blown. They could fix both for approx. 2800.00 and I said see ya.
I bought a seat sensor on ebay from a BMW with the same plug, plugged it in my buddy and I reset the light it lasted for 36 hours and came on again.
I also bought an amp on Ebay for 400.00 put it in and have not heard a sound from it either. Reading the forums here I had an electronics engineer check both amps he said they both read the same so we changed the switch modes in my old amp. But it still does not power up the radio comes on but also THE STEERING WHEEL BUTTON now will not change the stations. I am bumfuzzled. HELP!!!!!!
Do I potentially have a problem in one of the BUS systems?

 

The amp won't come on unless the radio tells it to over the iBus.
The radio won't unlock unless it detect valid iBus messages.
MFSW commands are sent over the iBus.
Do you have a 6 CD changer and is it working?
Do you have any non-BMW equipment in the car?
Do you have any other unusual behavior such as the blinkers, dash illumination or speedo not behaving as expected?

It is not necessary to connect the car to 12V while changing the battery on this vehicle.

 

I have a BMW seat occupancy sensor in the passenger seat, but it seemed to clear the code, but the airbag light came back on one night after about 36 hours of being off after the reset. I am not sure if the amp I bought on Ebay was good working condition. The wipers sometimes do stop in the center of the windscreen and will not restart on the wiper control until the key is turned off and back on. Sometimes I crank the car and the headlights do not come on for a minute after being switched on.....

 

Order this for you airbag issues. http://www.ebay.com/itm/OBDII-EOBD-BMW-Code-Reader-scanner-Creator-C110-V3-1-Hot-Sale-/161145336948?pt=Motors_Automotive_Tools&hash=item258502b474&vxp=mtr
Next throughly check the convertible related threads for likely places to check for evidence of water ingress. Do you find you electrical problems happen more when it rains?

 

Will the airbag light not come on if the car does not have 12 volt hooked to it while changing the battery?

 

i ordered the OBDII on Ebay . Thanks

 

Absolutely not.

 

As a point of pedantry, obd2 is a standard for communication with an engine emissions system and the gearbox only. It defines amongst other things only the connectors, the communications protocol and the basic codes for fairly vague faults. The purpose of the obd2 standard was allowing other garages other than the main dealer to interface with a car for basic diagnostics and smog/emissions testing.

What you've bought there is essentially BMW's INPA in a handheld device. Whilst the connector and protocol are compatible with Obd2 and the two are not mutually exclusive; it actualy supports the deeper level of messaging that BMW use to access more detail for each fault called DBus, along with accessing many other modules than just the engine and gearbox including the airbag, abs, nav, roof etc etc you can get detail such as error counters, engine conditions during the error, live data, reset adaptations and so on.