I've been trying to solve this mystery for a while now. My Jeep is a 2010 JK Sahara. When I switch the aircon on it takes about 20 to 30 minutes and the fan stops running on speed setting 1. I then switch it to 2, and after about a minute the fan starts blowing properly again until 20 to 30 minutes later when it stops again. The same for speed 3 and 4. If I park the car for about 10 or so minutes the fan works properly until the cycle starts again. This only happens with the aircon on. With the fan on and aircon off or with the heater on this issue doesn't come up. I have replaced the fan resistor and the fan but still have this problem. I must also mention that this is the old style aircon, not the facelifted version with the fancy knobs. Can anyone point me to a possible solution?