| Mine failed recently with the same type of symptoms. I could hear the fuel pump priming and when I tried to turn it over, nothing; but the interior lights would not dim at all and the voltage on the cluster test was somewhere around 12.3.
Ended up being my starter which is a bit of a pain to get at; but doable. I bought the part from OEMBimmerparts.com as it was only $50 more than a rebuilt unit and had free shipping.
Call around for pricing though if you don't want to DIY. I'd called my indy when elbow deep in this and his labor was going to be around $230. I don't know if he would have used the part I'd procured or what he would have charged for the part itself had I brought it to him; but at least it would have been closer to $500 rather than the $1000 I keep hearing about from a dealership.
Last edited by rbalazsi; 10-26-2012 at 06:43 PM.