You answered a question in reference to a Front Cigar Lighter Open Circuit. I have this issue and the fuse was no blown. Your answer was given at this url.
http://www.2carpros.com/questions/mercury-milan-2007-mercury-milan-my-cigarette-lighter-stopped-working

Where is the ground circuit G300 at center of left floor pan specifaclly located in the Driver compartment? I'm assuming you mean Left side panel maybe? Thanks
rcb3