what year/model your car is? different years equipped with different type modules... other than checking your as-built sheet (always nice to have that info handy), pop the left cover in the trunk, where the nav and/or cd changer would be... if you have a module mounted at an angle, then you might have TCU or a ULF... check to see if you have that module, then we will take it from there
oh, and put a signature of some sort, so we don't ask stupid questions, like what you drive...
of course you drive a bimmer... lol.. probably an X... could be X3 or one of the old or new 5s... but it is nice to know what you have...