Hey guys. 2000 xj owner, having problems with my heat. If i have the heat set on 1, 2 or 3 it doesnt blow at all. On 4 it blows, however it will be hot for a very short time then starts blowing cold. Both heater core hoses are warm to the touch, my thermostat is new.
Any suggestions as to where i should look 1st?

As always, any and all ideas are appreciated

 

switch contacts or resistor speed control.
core may need flushed.

 

There is a resistor for the blower motor behind the glove compartment that typically rusts out and that only allows the blower to work on high or 4. Use the search function here for "Blower motor resistor" and you will have information on the replacement part and instructions on how to replace the resistor.