When I turn on the heater switch, it will take a while to warm up before anything even barely comes out even on the highest setting. Then at some point it will start blowing out like it should and is fine. It has only done that a few times. Usually it barely blows anything out, but it is hot air when it does. The switch is supposed to vary the amount/speed of air coming out, but it doesn't work that way. Could I have a bad blower motor, or a bad switch?