Ford Focus: temperature control unit

my fan quit working on my control unit and i would like to try and change
it myself, i would just like to know how to get it out, and if there are
any special ways of doing it. i have a 2000 ford focus. It is a three
switch unit.

yes it is the cabin fan control on the dash, no it does not work on the
fastest, the first and second setting cut out last week, and then the 3rd
and the 4th just cut out this week. it would sometime work if i had it set
between the 3rd and the 4th, but now nothing.