Air conditioner wont cool off.

look at this link and see if it helps you out. 1999 jeep grand cherokee wont start Google Search

I would recommend flushing the cooling system and replacing the thermostat.....easy to do and only about $14 for a new thermostat.If that does not work then you either have a coolant leak somewhere or a bad heater core. I would also pressure test your cooling system before you flush the system to look for leaks in the system

there is a flap to redirect the air flow under the dash, it may be an item like a pen :) that has dropped down the vent opening stopping it from moving to redirect the air ... failing that, one of the motors/cables that operate the flap has failed

Likely your fan relay internal contacts have burned closed. Relay should be either in the power distribution center or in front of the battery.

Sounds like an electrical problem; look for loose, corroded or kinked/broken wires. The problem is most likely in the dash wiring/connections and seems to be pretty common in jeeps.

This could be an issue with the shift solenoid , but can also be caused by low fluid due to a leak, check your fluid. Is there a check engine light on, if there is it could be a solenoid issue.

Your freon level is low, and not circulating on slow compressor speeds. Stop by any shop that has a sign stating they work on a/c and they can recharge it for you in a few minutes. Here where I live they charge about $20.00 labor plus a charge for the freon they put in, they sell it by the pound.

relay sounds stuck...call a parts store for pricing

Run with rad cap off & heater on for about 2 or 3 times that rad fan comes on when it gets to operating temperature for cooling. Give it a little extra rev on gas pedal once in a while too, just a bit for a few seconds, to increase flow in cooling system for quicker disperse of air.

Try recharging the AC unit.