Okay, I've read some other posts on this problem, and i've tried several things to get this fixed, here is what I have:

1 - Defroster turns off after 3-4 minutes by overheating the 30amp breaker (replaced, not stock).

2 - I tried replacing it with a fuse, that just melted all the plastic off of it.

3 - I tried replacing the hvac control panel / timer with another one out of a 02 Z28 (I have a 97 SS).

None of these techniques worked to fix the problem. Has anyone found out anything else about what might be causing this problem?

 

Okay, tried a new trick to test the fus block contacts. Attached leads of two 12inch wires to each contact in fuse block, then attached 30amp breaker to the other ends.

Tested the defogger and it worked, I actually held the breaker in my hand almost the entire time, never got too hot to touch. Now I just got to fix the fuse block.

I hope this thread might help someone who has the same problem.