I have a ford focus 2001 wagon. My heater motor doesnt work on settings 1 -3 but works on setting 4. I have replaced the blower motor. I have also replaced the switch. Is there any thing esle i can try to fix it?

Third time's a charm. Would have told you to check the resistor first. Doh!
If it's any consolation, a bad switch is usually what makes the resistor go bad, but your old motor is probably just fine--sell it on e-bay!
Now, if I could only tell you where to find the resistor. Somewhere along the heater box between the switch and the motor. The resistors actually hang inside the box for cooling. It looks like the pick below with wires coming out. Some wires go to the motor, some to the switch.
Find it, take connector off, take 2 screws out. Pull it out of the heater box. See, it's all burned up.
Pay autozone $50 for a new one and get back to your life.