Last week I posted saying my wife felt her drivers side mirror wasnt defrosting. I found info here how to remove the mirror and just popped it off. I have 13.5 v at the leads to the mirror with the defroster on and 36 ohms across the heating element with power disconnected. Question 1: Does anyone here know what the resistance should be across the element, also, both voltage leads were black wires altho one was a positive voltage and one was negative. The mirror leads were not marked positive or negative on the mirror itself. Question 2: Does the polarity matter going to a heater element?