If your light switch makes noise...that's not good. If it makes noise, it likely is a buzzing or humming noise. There are a couple of possible reasons for this,and it the problem needs to be fixed immediately.
For the most part, light switches are cheap. Except for the contact terminals, light switches are made of plastic and they can break easily if someone slams their hand against it, but that likely is not causing the buzzing noise.
The buzzing or humming noise usually comes from where a wire connects to a terminal.
It may be that the terminal is damaged or corroded, but you will find that there is a loose or bad connection here. If there is corrosion, resistance can even make the switch warm to the touch. A loose connection causes heat and can obviously lead to bigger problems.
The solution is to replace the light switch. Also, if any of the ends of the copper wires are dirty or have corrosion on them, you can clean them up with some sandpaper. Turn the power off before you start working on the switch.
Here is some information on how to replace a light switch. Make sure that when you re-install the light switch the wires are snug in the terminals to avoid problems.
Remember the old skinny light switches that were usually almond color? They were great in the 1970's but now...not so much. It is easy to upgrade that to a more modern rocker-style light switch and while you are at it, upgrade the electrical outlets too. The rocker switches are wider and taller than the traditional switches. You can really go crazy with all the choices you have. Some switches are illuminated, and some don't move at all, instead they operate by sensing your touch.
You can buy new switches, outlets, and wall covers by the box and save some cash buying in bulk. Installing them is easy and requires only a screwdriver. Before you start, take an inventory of the number and kind of switches you will need. For example, the number of regular switches, dimmer switches, 2-way switches, standard outlets, GFCI outlets, etc. It's probably a good idea to get them in white rather than almond, as white looks cleaner is more modern.
Here is some information on how to replace a light switch. Replacing an outlet is virtually identical. Match up the wires to the switch or outlet terminals and connect them in the same positions...just make sure you turn off the power at the main panel.
At a customer's house today, her son came tearing around the corner and slammed his hand into the light switch to turn it on...all it did was break it. Light switches are cheap. For the most part, they are made from plastic with metal terminals for the wiring contacts. We generally aren't easy on them either. How many times have you slammed your hand into the switch expecting it to perform over and over again? Probably as many times as I have. Well, those cheap plastic switches do break but it's pretty easy to replace it with a new one.
This switch was a single pole, meaning it controlled a fixture from a single location. Three-way switches control a fixture from two different locations, and four-way switches control a set of lights from 3 or more locations.
Make sure you turn off the power to the location from the main electrical panel, and then remove the switch plate and finally pull out the switch from the box. Buy an replacement switch with the same number of screw terminals and wire it just like it came out. I don't advise using the push-in fittings on the switch, rather wrap the wire around the screw terminal. With a push-in fitting, you simply push the wire into the hole and it makes contact, however these fittings just don't seem to give the secure contact that wrapping the screw terminal does.
For this single-pole switch there are only 2 wires to connect. If you have 2 cables entering the box (meaning that the switch is in the middle of the run), you will have 2 black wires to connect to the brass screw terminals. If you have only one cable entering the box (meaning this switch lies at the end of the run), you will have a black and white wire connecting to the switch, although the white wire may have a piece of black tape at the end to signify it is actually hot (normally a white wire is neutral). You may also have a green screw on the switch for a ground wire, but the ground wire may be grounded to the box that holds the switch.
Make tight connections and secure the switch to the box and finally re-install the coverplate.