Air con / heater not working in my 2000 jeep grand cherokee no fan working no hot or cold air nothing

Check hoses going to heater core. Do both get hot? If so, problem may be a "blend" door failing to actuate due to vacuum leaks or bad actuator. If neither get hot, change thermostat.

replace the panel control or heat control valve

Jeep Grand Cherokee is notorious for broken blend-air doors. This is the door inside the A/C-heater housing that switches the air from hot to cold. You must remove the dash to repair it.

If the air-con working ok and full of gas it will be cold and the compressor clutch does click on and off. You say slow or weak air through vents. When was the last time the pollen filter was changed as heater motor air may be restricted by this if dirty or heater motor performance poor.

most likely there is a door in the dash somewhere that controls the flow of the air. the actuator that controls the door for that side might be bad

Probably broken blend doors if everything else is working, but its just blowing cold air. Do a google search for "Jeep Blend Doors" or "Heater treater" for more info.

Check to see that the blend door linkage is hooked up. Doubtful it is heater core, as you had heat to one side and not the other. Check coolant control valve linkage, verify it is moving the coolant valve from off to on when you switch temperature from cold to hot. Verify you have coolant flow to the heater core by feeling the heater hoses where they enter the firewall. If all checks out well, then look at hvac controls individually.

Check the coolant level, sounds like you may be slightly low....Be sure heater is on high when filling the system....Look for any air bleeds...

You say that the air con is not cold, i think the problem would be the aircon will need regasing, if the gas has escaped from the system, the temperature in the aircon system will always be warm so the fan will continue working attempting to cool it down. It will need checking for leaks, most companies that recharge the system check the whole system for leaks first before refilling the system. If its the engine cooling fan it could be the thermo switch that is faulty,the way to check that is when the engine is cold disconnect the wires from the switch and put an ohms meter across the swith it sould not give any reading, it will only show a reading when the engine reaches operating temparature. hope that helps. regards Richard

Pass. side blend air door motor is probably bad.