Is it possible to wire somthing that uses a 9v battery into the car. For example using a 12v source, but using a 12v to 9v converter? is there such thing?

 

no , yes? bump

 

Im not exactly sure, maybe someone can help me out on this, but you should be able to find some resistors that will do this for you. Check at your local Radio Shack or something...theres a formula somewhere for choosing the right one, but I have no clue where. Good Luck!