winter is coming

[Cat1cat@aol.com]

winter is coming and the rear window on my 71 bgt didn't get warm
finally got 12 volts on the white/black wire and ground on a black wire
coming from the car      so that looks ok

on the lid there are three wires     2 black      and one     blue/white
there is no continuity  between any of the wires

i figure the heater is shot       is there any way to repair the heater 
it is that
has the very fine heater wires

open to any hints
thanks 
rocky in Lansdale pa