Fan won't change speed on ZX2

[Plum Ranger XLT]

On my mom's 2002 Escort ZX2, the fan setting for the defrost and the like, for some oddball reason it works fine one day then the next day it won't change speed when the fan setting is changed between the high and low settings. Any ideas?

 

[kimcrwbr1]

sounds like the switch or the connector for the switch if the resistor goes bad it usually stays bad. Did someone mess with the radio maybe the connector got jarred loose.

 

[ra49686]

Most likely it is the blower motor resister,mounted in the air box. ECH BR286
at a napa store and about 20 bucks .Heater motor will only work on high when they go bad.Also look at the plug,which can get burnt causing what you describe.