How to Diagnose Common Electrical Switch Problems

a row of electrical switches on a wall
  • 1 hours
  • Intermediate
  • 10
What You'll Need
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 that 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's ON, 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 burnt out. Light bulbs can burn out very easily and they 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. Turn the dedicated circuit breaker back OFF to prevent any potential risk of danger for yourself, then take the faceplate off the switch and inspect the wiring. All of the wires should be neat and tidy, all connections screwed in tight.

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 the switch closes when it's flipped on.

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 a 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. At this point, it is best to call upon a professional electrician to seek advice and to get it repaired. A DIYer needs to be very comfortable with electrical work to venture into a rewiring project.