wiring to the roof vent of a 318 BHS

[Davevod]

I have a 2013 Lacrosse 318 BHS and I was thinking of replacing the main roof vent with a maxair or fantastic fan. Does anyone know if there is already wiring to the main vent or will I have to fish a wire from somewhere. I am going to the storage area tomorrow to take a look but was hoping to find out information ahead of time. Thanks.

[Tula]

I installed a Max air in bedroom....if you remove stock vent and feel around, you should find wires as i did....find which is the hot wires for 12volt and connect to new fan which has it;s own switch...I had no problems doing this way