when the knobs are turned to select either defrost or floor heat the unit does not switch. does this mean the unit is bad or should I start with a disconnected air duct or what?
problems with the climate control switches. on 2004 Jeep Grand Cherokee
Could be a number of things. Most likely would be the mode door actuator. A good repair shop should be able diagnose this for you.
do not guess,have a diag done to make sure