1994 Mercury Grand Marquis. The after market film has been there for 14 years. Removing the side window film should be no problem with heat & razor blade. The rear window has a defroster wire. It is feared that a razor blade would damage this wire. Any suggestions? Additionally, how do you deal with the remaining adhesive on the glass after the film has been removed?

Try 91% isopropyl alcohol on the remaining adhesive. Spray it on and let it soak. Then try removing with a razor blade. I'm not too sure you'll be able to remove the rear window film due to the defrost coil. Try calling up one of the places that does window tinting and ask them if they do rear window removal of film.