Testing rear defrost
 

I'm not sure if the rear defrost is working. Can someone tell me how I would test it?
I thought I could unplug the lead to the hardtop and see if I get power. What should it read? What else can I do short of waiting for snow?
If the defrost is toast (pardon the pun) due to the lines on the glass being cut, what are my options if I want to have it work?

The ETM shows a black wire providing power to the heater element, and a brown wire providing ground. Both are 2.5, so they will be substantial. So you can unplug the connector, remove the back off the car side connector, and:

- test the brown wire for ground
- depress the switch (engine may need to be running) and see if you get 12V between the black wire and brown wire

Then locate the pins on the top side connector where the black and brown wires connect. Test the continuity between these pins, and you should see some resistance since that's what generates the heat. If there is no continuity/resistance, then the element in the window is probably bad.

So if you have power, ground, and continuity, you should have a working defrost.

The old fashioned way is to turn the interior light on.....then the rear defroster. If the light dims from the defroster drawing power then chances are it's working. Not 100% but a quick test.