Half moon symbol?
 

On the far left side of the heating, ventilation display, I now have what I'll call is a half moon sticking out from the side. What does this mean? It was never there before.

Sorry, but this means that your heating and a/c unit's backlighting is about to go out/become totally distorted for viewing.

bummer
 

Thanks Boxtaboy......that is certainly disheartening though. Is this a common occurrence? How much longer until I can't read anything on the display? Guess we're about to find out whether my extended warranty policy is worth its salt. It did cover a faulty ignition switch a few months back.

i have that too...this is what i do.
full heat when its cold, if its warm, top down :D

but yea, it happens to a lot of them though, you can get one on ebay when they pop up for like 100 bux or so usually

I'm not sure how long it will take till the display goes totally crazy, but it looks like this, right? It hasn't happened to me yet, but I hear the replacement LCD panel is around $400, or you can perhaps get one from ebay or a dismantler. Good luck.
http://www.pcars.us/albums/3983.jpg

That's it!
 

Boxtaboy, yup, that's exactly what it looks like. In my case the light has only been on for a few days.

Still waiting for a review of this replacement LCD display.

http://www.986forum.com/forums/showthread.php?t=2951&page=1&pp=20

That 70s Display
 

My left number display on my unit only lights up several bars in the 70's. Oddly enough the 60s and 80s work perfectly. I found a replacement from Oklahoma Dismantlers but the lowest they would go was $300. For that price I thought I could live with the problem for a while longer.
Good luck with your back lighting issue.