Lee: The X10 brand wall switches (both
regular and 3-way) are the least reliable of
all the modules since they don’t have a
neutral wire connection. So if one module is
going to stop working, it will most likely be
a wall switch.
If you CAN’T remotely turn the light ON, but
you CAN remotely turn the light OFF, the
problem is likely something (probably on the
same circuit as the switch) generating
electrical noise. The cheap X10 modules
don’t have automatic gain control, so even if
your signal is stronger than the noise, if
the noise is too strong, the module won’t be
able to distinguish between the two. Turning
the wall switch on will weaken the noise (and
the signal) and may make it able to
differentiate between the two (this isn’t
true for lamp and appliance modules).
I would start by unplugging (not just turning
off) electronic equipment on the same
electrical circuit as the wall switch. If
the equipment that is causing the problem
isn’t on the same circuit as the switch, I
would then try turning other breakers off to
find out what circuit it is on (don’t turn
the circuit that the controller is on off
though). Once you have found the problem
equipment, you then need to plug it into an
X10 noise filter.