How to Diagnose Common Electrical Switch Problems

What You'll Need
Circuit tester
Light bulb
Replacement switch

Electrical switches make it very simple to control lights and appliances. However any problems with these switches can be very frustrating and annoying. Learning how to diagnose these problems will save you a lot of time and money.

Step 1 - Check the Fuse Board

The first thing that you should check is that the switch hasn't tripped the circuit breaker for any reason. There are a number of things which can trip the circuit breakers. This is one of the most common problems and will only take a couple of seconds to put right. Identify the circuit breaker linked to the electrical switch in question. Even if it looks like it is one, switch it off and back on to make sure that is not the problem.

Step 2 - Check the Light Bulb

a women replacing a light bulb

Before you bother doing anything else you should also check that the light bulb hasn't blown. Light bulbs can blow very easily and this might need to be replaced. It's worthwhile replacing the light bulb to find out whether or not that will solve the problem. This should only take you a few minutes and even if you have to buy a light bulb it won't go to waste because it will be used eventually.

Step 3 - Look for a Shorted Switch

Another very common problem is a shorted switch. If any of the connections inside your switch are frayed then this can cause them to short out. This will prevent the switch from working properly and could also be a fire risk. Take the faceplate off the switch and inspect the wiring. All of the wires should be neat and tidy.

Step 4 - Test the Switch

Use the multimeter to check that all of the connections are made properly and accurately. Also use the resistance mode of your multimeter to check that wires are connected properly and that none of them are broken.

Step 5 - Replace a Faulty Switch

wiring a light switch

The switch could also be completely broken or damaged. If this is the case then it will need to be removed and replaced. Replacing a faulty switch is actually pretty easy.

To get started, make sure you turn off the electrical power to the switch. Then simply use a screwdriver to remove the faceplate of the switch and then use an electrical screwdriver to loosen the terminals. Once the terminals have been loosened it's then possible to remove the wires and attach them in the same way to the new switch.

Step 6 - Wiring

If all else has failed then there's a good chance that the problem is caused because of the wiring and not the switch. Wiring problems can occur for a number of different reasons, including rodents biting through the wires. Rats and mice often bite the wires which will cause the insulation to be lost. If two of these bare wires touch then it can short out the circuit and be very dangerous.

The only way to repair these wiring problems is to rewire the whole circuit and possibly your whole house.