Light controlled with light switch?

Well, i suggest this:

1. Your LightSwitch should have a ClickDetector inside it.
2. your Light part should have PointLight, SurfaceLight or SpotLight inside it.

local LightSwitch = workspace.LightSwitch --Imagine your light switch is in Workspace.
local Light = workspace.Light.PointLight --Imagine you have a part where there's a PointLight, disable the "Enabled" property of PointLight.

local LightOn = false --This tells the script if the light is on or off, if you want your light to be on already, change the "false" to "true"

LightSwitch.ClickDetector.MouseClick:connect(function() --When you click the Light Switch...
    if LightOn == false then --If the light is off when you click the Light Switch...

        Light.Enabled = true --The light will turn on.
        LightOn == true --This tells the script the light is already on.

    elseif LightOn ~= false then --If the light is on when you click the Light Switch...

        Light.Enabled = false --The light will turn off.
        LightOn == false --This tells the script the light is already off.

    end
end)

Hope this helped!

Make a model with 2 parts. Insert a PointLight into the part that will have the light, and a ClickDetector into the switch. Now insert this script into the Model

local Light = script.Parent.(name of the light soruce)
local Switch = script.Parent.(name of the switch)
local On = false

Switch.ClickDetector.MouseClick:Connect(function()
    if not On then
        Light.PointLight.Enabled = true
        On = true
    else
        Light.PointLight.Enabled = false
        On = false
    end
end)

Make sure that the light is disabled by default. If not change "On" to false