I dont know what the problem is. Im hoping its not the heating core :(
My heater only blows a little bit of hot air when the knob is turned to A/C? on 2003 Jeep Liberty
Try all fan speed settings. If the fan does not change for each setting then it is probably the blower motor resistor. Be sure fan is operating 1st.
AGREE W/ BAK OR GET DIAG AND EST