Heater does not work in Cherokee?
The Grand Cherokee is notorious for failures of the air flow control. However the Cherokee has the same basic problem. The blend door has a tendency to break, killing control over air flow through the heater core. The fix is fairly simple with the kit from HeaterTreater. Check the product at heatertreater.net.
1. Is coolant flowing through the heater hoses and heater core? Once the care is fully warmed up, running, and the heater on, the hoses going to and from the heater core should be hot to the touch. If not, coolant may not be flowing. 2. Is the heater door, under where people's feet are, broken? This URL may help explain http://www.heatertreater.net/jeep Cherokee 97-04.html