I also have a 2000 jeep wrangler. This year has a problem with the heater core plugging up. You can either try to flush it out, or just replace the heater core.
Clogged Heater core... common problem with 2002 dodge
heater core could be rusty and old or line to heater core could be plogged most likely old heater core
Heater works fine in my Wrangler! Check the thermostat or the hoses or heater core might be plugged. The thermostat is easiest ^ cheapest to change so start there.
Heater core needs flushed.
Leaking heater core
Yes. It has a heater core in the dash that has air blown over it to heat the passenger compartment.
the heater core has got a hole in it or your top has a hole init. If the water is green it is your heater core. if not it is your top.
free diagram step by step at www.jeep4x4center.com
The most common signs of a heater core problem is either leaking antifreeze or a mist coming from the air vents. There will also be a sickly sweet smell in most cases.
The heater core is leaking. Replacing the heater core is your best bet.
Vent bypasses heater core when open,it is for outside air only...I know this because I just replaced heater core.