If it is the resistive lines (on the window) themselves that are cracked, find the cracks (either visually or with an ohm meter). You can either buy a pen at any local parts store (e.g., Pep guys, Autohome ) or buy a pack of juicyfruit (or any other flat wrigley's gum), chew the gum but do not throw away the silver wrap; instead, these wraps can be separated into a very thin (!) alu foil and the paper that this foil is resting on (takes some time to figure it out). you can rub small pieces of the foil onto the cracks so the lines are connected again... (Clean the window first.)

Hope this helps