Fuzziness, crackling, pops or cut-out of your guitar's sound, particularly when you know your cable is in good working order, is a good indication of loose or broken output jack wire. Fortunately, wiring a guitar jack is one of the easiest repair jobs you can perform. The task usually can be performed in just a few minutes or so, and even someone who has had no previous experience with guitar electronics can do an acceptable job.
Remove the control cavity covers, or in the case of Stratocaster-style guitars, the pickguard assembly, from the guitar.
Unscrew the jack plate and carefully pull the jack away from the body of the guitar. Cut the wires connecting the jack to the controls.
Cut two lengths of new guitar circuit wire, one approximately 6 inches long, which will serve as a ground wire, and the other long enough to reach from the output jack to the pickup selector switch, if the guitar has one. This is the hot wire. If the guitar is a single pickup, cut the second length of wire 6 inches as well. Strip approximately 1/4 inch of insulation from all four ends of the wires.
Desolder the old wires from the connections on the jack. To desolder a connection, touch the tip of the hot soldering iron to the connection until the solder begins to melt. Gently tug at the wire until it comes loose from the connection point. Desolder the old wires from the connections on the bottom of the casing of the volume pot and either the pickup selector switch, if the guitar has more than one pickup, or the center tab on the volume pot if the guitar has a single pickup.
Solder one end of the new ground wire to the ground (ring) tab on the jack. To solder a connection, hold the exposed core of the wire against the connection point. With the same hand, hold a 4- to 6-inch section of rosin core solder directly above the connection. Hold the tip of the heated soldering iron against the end of the section of solder until it begins to melt. As the solder begins to flow onto the connection, remove the soldering iron from the connection and allow it to cool.
Solder the one end of the hot wire to the hot (tip) tab on the jack.
Thread the wires through the jack hole in the body of the guitar.
Solder the other end of the ground wire to the bottom of the casing of the volume pot.
Solder the other end of the hot wire to the appropriate tab on the pickup selector switch if the guitar has more than one pickup, or to the center tab on the volume pot if the guitar has only one pickup.
Fit the jack plate back in place and secure with screws.
Replace the control cavity covers, or if it is a Stratocaster-style guitar, the pickguard assembly.
Always ensure that electric guitars are unplugged from the amplifier before performing service to eliminate the risk of electric shock.