The pickup switch is generally referred to as the toggle switch. It controls the different pickups on the guitar. It makes it possible to isolate the pickups or to play them in combination. A common problem with the Epiphone Les Paul is the toggle switch. Epiphone Les Paul guitars are more affordable than their Gibson counterparts, but the quality of the materials isn't as good and this results in problems such as a faulty toggle switch. The most typical toggle switch problem is contamination and corrosion. Nevertheless, this is an easy fix. A more serious problem may require replacing the toggle switch.
Manipulate the toggle switch to diagnose the problem. The toggle switch on an Epiphone Les Paul has three positions. The left position, in which the toggle switch is pointed towards the fretboard, controls the neck pickup. The middle position controls the neck and bridge pickup. The right position, in which the toggle switch is point towards the bridge, controls the bridge pickup. Play your Les Paul through an amplifier and move the switch back and forth. Scratchy sounds indicate that the switch is dirty or corroded. Intermittent sound, or no sound, iindicates that at least one wire is loose or the switch is worn out.
Lay the guitar face-down on a soft blanket or towel to protect the guitar finish.
Remove the toggle switch cover plate on the back of the guitar with a Phillips head screwdriver. This gives you access to the toggle switch and wires.
Clean the toggle switch with contact cleaner. Move the switch back and forth several times to help work the cleaner into all the areas of the switch. Plug the Les Paul into the amplifier and test it out to verify whether the scratchy noises have disappeared.
Examine the pickup wires that are connected to the toggle switch if you're experiencing an intermittent sound problem. If the wires are worn and frayed or not connected, they need to be reconnected to the switch. The wires are color coded. Take a picture with a digital camera to use as a reference before removing the wires. Heat up a soldering gun and remove the wires from the toggle switch. Then replace the wires by re-soldering them.