I went to use my rear defrost this morning, and after having it on for over 10 minutes it didn't do anything to the frost on the back window. The light comes on, and I can hear a click from behind the dash. I checked the fuses and they all look fine, so I pulled out my stereo thinking something might have not got plugged in when I had my stereo installed. I ended up finding this plug not plugged into anything, but I couldn't find anything to plug it in to. Could this plug have something to do with the rear defrost?
http://sio.midco.net/homercf/plug.jpg

That plug may be for the lights in the original stereo unit.

I looked on the original stereo, and there's no spot for that plug. The plug is actually coming out of the plug to the left, and I think that one goes to the climate control wire harness.

well if you're getting a light on for the defrost the climate control or what not should be plugged in since you're getting power there. i'd recommend checking out the electrical diagram for the defrost unit. if you need help reading the schematic then let me know.

Do the tedious task of looking at the defroster grid on rear backlight for any breaks and check to see if either wire to the backlight has been disconnected, or worse, if the actual connector has separated from the backlight.

There are kits out there to fix a break in the grid. There are also kits/special solder to reattach a separated terminal from the backlight.

Broken wires are fixed in a normal manner -- butt connectors; solder and shrink wrap tubing; etc.

Good luck.

I guess I'll just bring it in to Subaru and let them figure it out.