With the popularity of window film tints, the defroster grid lines are exposed to possible damage from tint installations.  This gets worse when trying to remove old tint films.  Be very careful with metal razor blades that can easily cut through these conductive traces.  If you do cut through one of these electrical traces, you can sometimes fix them with a "silver" conductive pen; these are available from electronic supply shops and are used for IC board traces.

Questions?  Comments?  Send mail to:  reted@fc3spro.com