I have an 01 Jeep Cherokee Sport. I am having

While it doesn't seem likely, if you've changed, or had the thermostat changed.... I'd say you got a faulty thermostat. I am curious as to what your temperature gauge says the temperature of the engine and coolant is.. If your gauge is showing hot, I can think of two more possibilities... the water pump isn't pumping right... and, if the water pump isn't working right, the problem can be a cracked head or block, which can cause an airlock in the coolant system. Check the coolant or radiator cap.

I would have the thermostat replaced and have the antifreeze flushed or drained out. If the thermostst is over 4 years old and if the coolant hasn`t been flushed or drained out recently, then this will improve your heat situation..

Check out your cold start choke. It is designed to cause your fuel mixture to run "rich" until it warms up. It is basically a heat sensitive coil that reacts to heat from the exhaust manifold.

I tried that but not my heating core is not getting hot just warm. i think they computer is turning it off because it still thinks the doors an closed. This is what im trying to figure out. I felt the heating hosing under the hood and they both feel hot going in and out of the heater. I am getting luke warm air which is better than the freezing air though

Your heater control valve is pluged or not opening all the way,I hope this helps you

Since your blower is working and it is a heat issue,thats where we'll start,First thing is have you checked the coolant level in the radiator when engine is cold,make sure it is filled to top,next verify you have coolant in reserve ,Start your van and get it up to normal operation temperature,If your heat gauge on the dash works correctly it should be 190 degrees,Now lift the hood and locate the two heater hoses going into the heater assembly at the fire wall,Both hoses should be hot to hold on to,if both are hot and no heat inside your problem will be the blend air door in heater assembly.
if neither hose is that hot you need to replace the thermostat in the engine to get it up to 195 degrees.
if one hose is hot and one is luke warm then the heater core is blocked and to blame. hope this helps you.

The Blend door in the HVAC box. Unfortunatly this is the main cause of this type of problem u have to remove the dash and replace the blend door and the acuator.

check vent functions to make sure in heat position vents are fully closed. turn temp switch back and fourth so hear movement of heat vents gl

YES, THEIR IS A HOT WATER CONTROL VALVE, ITCAN BE OPERATED BY VACUMN, OR CABLE, VAC, TYPE WILL HAVE AVACUMN HOSE TO IT, PLS CHECK IT FOR CONDITION, CRACKS, SWELLING, IF OK, THEN WITH ENGINE RUNNING, HEATER CONTROL IN HOT POS. PULL HOSE OFF VALVE, PUT FINGER OVER END, FEEL FOR VACUME. IF THERE IS, MOST COMONLEY RESULT IS THAT VALVE NEED TO BE REPLACED.

The heat control valve, this is the valve that allows hot engine coolant to flow into the heater core inside the dash , if its decective it will not open to let the coolant to flow.
The Thermostat if it is bad (stuck open) the car will not warm up and will also cause a no heat problem as well as many other issues.
Does the car warm up quickly and reach operating temp within about 5 min?