My 1997 Altima heater/ac fan only works on setting # 4. (Full Blast). I get plenty of heat or ac on 4, but thehurricane force winds or nothing option is an annoyance. Is the problem more likely in the switch or the resistor? Any help would be appreciated.
That sounds like the classic blower resistor that has burned out. Usually the highest fan setting completely bypasses the blower resistor, so it will still work on high. Some newer cars do this all electronically, but if you can find a blower resistor listed, its probably the first thing to check out.
They are usually installed into the heater box inside the car, most of the time somewhere on the passenger side. The reasoning is that they get quite hot while running, and inside the airbox they get force cooled by the fan.
Look up the part online and see if you can find a picture, most likely you will only see the part that the wire harness plugs into, the rest will be inside the airbox. You can probably get away with a visiual inspection to see if it is burned out, if you don’t have access to a multimeter, or don’t know how to use one. Some autoparts places do not accept returns on electrical parts. So it may be worth checking it out before you buy a replacement.
Your mileage may vary.
There are ways to check such things to be sure, so you don’t have to guess. But you do need a multimeter. It is true, however, that what you have now is exactly what you get when a resistor blows.
Note that sometimes a resistor blows because the blower fan is drawing too many amps. That can be tested too but its more complicated.
Thanks! I have an Altima repair manual and have located the resistor. Looks like a pretty easy fix which will get me big points with my wife as she LOVES this car.