Blower speed problem

My fan only works on setting 4, this is the 3rd time this has happened both times before it cost me almost $500 in repairs and I don't think that it should. A friend suggested that it is a simple case of replacing the resistor and that part is approx $40. Can you tell me if that is the most likely cause and how easy is it to change the resistor?

I believe that you friend has hit it right on the head. It sounds like the blower motor resistor has failed. On this car the blower motor is behind the glove box on the passenger side. To access it remove the screws (I believe there is 4) along the bottom of the glove box and take the glove box out. Once it is out you should see the blower motor housing. There will be 3 bolts holding the blower motor in from the bottom. You should find the resistor in the same general area as the blower motor. Hope this helps. Good Luck.

Heater problem
2000 Ford Focus 4 cyl Front Wheel Drive Manual

The heater/ventilation system seems to work on settings 1, 2, & 3, but when I switch it to setting 4, it does nothing. Also when I switch to setting 4, the overhead dome light seems to flicker. This car has no A/C. I have replaced the blower motor resistor, as it would have been a cheap easy fix. If anyone has a good idea to start with, I would be very appreciative.

The blower motor resistor may have still been good. A lot of them default to the highest setting if they go bad. It may be that the switch itself is bad and not making a contact anymore at the #4 setting. Sounds like you are handy, I'd pull the center of the lower dash apart where the heater/blower speed switch is and swap that out for a known good one.

Heater problem
2000 Ford Focus 4 cyl Front Wheel Drive Automatic 112k miles

Have a 2000 ZX3. Heater motor only blows on low speed. Just replaced the resistor block, even though when those are bad it usually only blows "hi". It's getting really cold up here in the North country, and my girlfriend is in need of heat/defrost. Any help would be appreciated.

Thanks!