Rear defrost not working

[Gods_Son]

When I press the switch it does not illuminate leading me to believe that perhaps that is the culprit. The fuses are good (8 & 23)

-Is there any way to test the switch?
-Best way to remove the switch? (flat head is too thick to fit)
-What tests can I perform with my multimeter and how? (never diagnosed defrost problems before)
-Rear grid appears to be good in that there is no visible brakes, corrosion etc...

[AndrewBird]

Disconnect the wires to the grid and use an ohm meter to check the grid. Should measure zero resistance or very low. If it reads infinite, there is a break in the grid somewhere. If this happens, slowly move one probe down the line of the grid until you get a reading. When you do, that is where your break is. You can buy paint pens to fix it.

The switch just pushes out from the back. Easiest would be to pull the radio to get to it from the back. Then just check for continuity across the switch when it is on.