Where is the heater control valve located in 2000 jeep wrangler

2001 jEEP WRANGLER either 2.4 or 4.0 even if the production date is 2000 you dont have a EGR (exhaust recirculating valve)

your heater core is probably clogged try flushing the system

check the heater control valve, it is located on one of the heatercore hoses in engine compartment,

If you have a heater control valve on the hoses going into the heater, make sure it's working. Heater core can be plugged, most times they can be cleared by removing the hoses to it (not at the firewall...it's too easy to break the core extensions) drain it and fill it up with white vinegar.(keep the hoses higher than the core) Leave it sit about a half hour and run a garden hose through it. Last but not uncommon is that a vacuum motor that operates a door inside the heater plenum can be bad or the door itself can jam. To remove the heater to service either the core or any of the doors etc is generally a large job that you would need to get a manual for. (most of dash needs to come apart) Hope you find the problem before it comes to that!
Good luck

Sounds like the blend door that diverts air flow inside the heater box is not working, or, the heater control valve on the heater hoses in the engine bay is not closing.

its located on the throttle body, and yes its pretty easy to replace

When I drive my 2000 Jeep Grand Cherokee I can hear water. I was told to blow out the lines of the heater core with a compressor. Where is the heater core located?

which computer? there are a few but i think you mean the PCM or Powertrain control module. that is bolted to the firewall behind the battery

The tube that comes out of the top of the valve cover is your pcv.
The grommet that it goes into gets blocked.

You could have a bad heater control valve that is located under the hood inline with one of the heater hoses.