Did you recently install tinting
because certain types of tinting will block radio signals
but it should work inside the car anyway.
Are you sure the battery you installed was good and put in
the right orientation.
Do you have a voltmeter to check these things?
If the keyfob is brand new did you get it progammed for the car
with the comfort access option programmed?
Also if its brand new do you have any kind of warranty on it?
electical e90 pdf
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU