HVAC fan not blowing air at any of the four speeds. Replaced the blower, speed selector switch, resistor, and the AC / Heater control switch. This seems to be a problem on the majority of the Jeep Wrangler TJ's. After looking into it, we've found that many '99-and-later TJ owners are experiencing loss of control when it comes to the HVAC system in the Jeep. The issue is, as hours accumulate on the blower motor it wears down. As the brushes in the motor wear, the motor itself is subjected to more dirt and debris, and eventually, it will require more amps just to turn. In fact, it takes so many amps, the blower-motor switch and associated wiring just isn't rated to handle it. Like all electric things when they're overloaded, the switch heats up-when that happens, more resistance is created, more juice is required, and so on. Different Jeep owners have reported the speed selector switch melting, others the AC Heater control switch, some the wiring at the resistor.