Blower Resistor
 

Where is the blower resistor located on 2008 model

The fan will blow on low but that is all. It will not blow on high. Is this the resisitor gone bad?

That sounds backwards to the norm. They usually run on high and no lower speeds if it is the resistor because high usually bypasses the resister.
I would suspect the switch itself.

Is the switch much trouble to change?

I wouldn't think so. I haven't disassembled a Caliber dash yet to tell. I would get a test light or meter to check for power at the resistor on different speeds. It is easier to get to than the back of the switch. There should be 4 or 5 wires on the resistor. 3 are switch inputs for low, 2 & 3. The 4th could be high from the switch (not all cars wire this way) and the last one is the output to the motor. You should get voltage to a different wire depending on the speed switch position. If you only get it on the one speed, then more than likely it is the switch.

The wiring is so tiny on the blower switch that I doubt it would carry enough current to run the fan thru resistors. However, I would expect there to be a relay to allow full voltage to the fan blower motor when switched to high. I have had a wire break on my PT Cruiser to the resistor assembly (found after replacing the switch and resistor assemblies) that the wire is simply 'open' and ran a new one and jumpered each end.