Changed heater core today, I had been running with the heater core bypassed. With the new one installed I do not have heat. The fan is working, the vent selector is working, the only thing that doesn't appear to be working correctly is the blendor motor. I can hear it make noise only when I move the dial from the coldest setting up about a quarter of the way. And that is it. I guess the reason for the post is, does the blendor motor run the entire time that you turn the dial or just a little bit as I described previously? By the way I have replaced the water pump, thermostat, and heater core. It looked pretty nasty from the previous owner who it appears, had used some stop leak product. 2001 Cherokee Sport 4.0L

 

does the ac blow out the correct vents if not check for vacuum leaks at vacuum canister to vacuum lines going in around blower motor

 

I am not sure exactly what my problem was but I did add more coolant and my wife drove it today and the heat worked great. Maybe I was just impatient anticipating some sense of accomplishment after the changing of the heater core.

 

kool