A few weeks ago the heater only works on high. The fan doesn't work on the lower settings. Someone at work said it might be the heater resister. Does anyone know, if so where is it located.
Thanks

Find a bundle of wires near the fan motor under hood. When you only get high speed it is because the thermal fuse in the resitor assembly has opened. Sometimes this is just the result of age because the fuse is chemical. It is supposed to open when the resistors get too hot because of blocked air flow or the motor is drawing too much current. Resistors will overheat at much lower currents than the fuse is rated at. This thermal fuse is available at Radio Shack for under $2. Looks like a silver diode. It must be crimped in because soldering it will make it pop. Even if you go the junkyard route, the new one may go bad if you don't correct the fault.