Changing a light bulb sounds like an easy process, and sometimes it is. However, there are important safety measures to keep in mind. Sometimes, you will need to replace a light bulb that is trickier. For example, perhaps the bulb is in a very high vaulted ceiling or is a car dome light.
When a working switch ceases to be able to turn a light off, it is almost always a bad switch.
Turn the power off at the circuit breaker.
Remove the switch cover.
Take a picture of how the wires connect to the switch
Remove the old switch
Replace with the same type of switch, matching wires
Put cover back on
Turn power back on
This assumes that only one switch controls the light. If there are other switches in the circuit, such as a 3-way or 4-way setup, one of the other switches could be the problem.
