Just putting my 2 cents here.....my AC and heater stopped working this past January on my '98SE....turned out I need a new "heater core"...not sure if I said it right, but I believe thats what the part was called.....anyways, it ran me around $900+ at the dealer to get it fixed.....I hope thats not the same thing that you have.
Definitely check the coolant first. If that's OK, there may be a couple problems going on here.
If the coolant's brown, or hasn't been changed in a while, you'll need to flush the coolant system. Here's some instructions that were written by one of the most highly intelligent people I've met. :blink: Coolant Flush
Also, the heat and AC not working may be unrelated. One does not depend on the other to work correctly. A few questions:
-Do you have auto or manual climate controls?
-When you turn on the AC, does the compressor engage?
-When you turn on the heat, or AC, does the blower fan work?
Let us know what's going on, and we'll do our best to get you squared away.