You just probably
don't see it.
First, get teflon
tape and wrap the
threads with tape if
there isn't any on
it. If there is, you
don't have to.
Next, turn power
off. Now open the
access and you will
see the metal
control box. On the
bottom of the box is
a steel tube; that's
the heater.
You didn't tell me
which model you have
so I will presume
you have the model
with the heater
strapped to the
outside of the box.
This being so, if
you look to the left
backside of the
heater you will see
the switch. It has 2
wires coming out of
it. Disconnect the 2
wires (order doesn't
matter).
Take a open end 1/2"
wrench and remove
the old switch. If
you have water, just
move quickly. I do
this all the time
with water in the
spa. Tighten to
snug. No direction
matters. Plug the 2
wires back in.
Viola!