The above pictures showing you the location of shifter cables .
The following is teaching you how to remove them.
1.Shift your bicycle into its highest gear to put less tension on the shift cable. Locate the derailleur, which is mounted near the rear wheel hub on the right-hand side of the bicycle. Locate where the shift cable comes into the derailleur. Remove the end cap (if equipped), located on the protruding end of the shift cable, by grasping it with a pair of needle nose pliers. You can also simply cut the wire behind the cap with a pair of wire cutters.
2.Loosen the cable retainer on the derailleur with a Philips screwdriver or allen wrench, depending on your brand of derailleur. Now pull the cable out of the derailleur and let it hang. Remove the cover from the shifter located on your handlebars by rotating it counterclockwise by hand. Locate the end of the shift cable, which should be visible after removing the cover.
3.Pull the entire length of the shift cable slowly and carefully from the shifter and the plastic cable housing. (Note: The cable has a metal cap on its end. You may have to push the shifter spring slightly to the side to reveal the cable cap and the end of the cable.) Discard the old cable once it has been removed.
4.Feed the new shift cable into the shifter housing in the same direction the old cable was pulled out. Fish the cable into the plastic cable housing by hand until the cable protrudes from the other side of the housing near the derailleur. Pull the cable tight so that the end cap fully seats into its slot in the shifter assembly.
5.Feed the cable though the slot in the derailleur and pull it taut. Tighten the retainer screw on the derailleur to secure the cable. Leave approximately 1½” of cable protruding from the end of the retainer for future adjustments. Cut the remainder off with wire cutters.