I have a ceiling fan with lights. A while ago, I noticed a burning smell whenever the incandescent bulbs are lit. That smell was coming from the area of the wall switch (a dual control unit). The wires all seem fine in there (no signs of melting, etc.). The breaker has never tripped, but the lights seem to flicker a bit. Can such controls just "go bad" over time, and need to be replaced? This Leviton unit must be 12-15 years old. It''s 3-wire (red, yellow, black), 4-speed fan, high and low settings for lights.