This is 100% true. The rear window defogger goop has a lower conductance than say copper or aluminum but it does conduct. The stuff gets hot when it conducts (due to a relatively high resistance for a conductor) like a heating element on a stovetop or an electrical heater.Originally posted by: KF
The rear windows of cars sometimes has lines of conductive material on the surface. Electricty is run through it to heat up the window to get rid of the condensation that forms in the winter. Those lines somtimes get broken. They sell a "rear window defogger repair kit" that has a tiny bottle of conductive paint. It it didn't conduct electricity, it couldn't possibly repair the lines.