One side is not working. The

It's definatly a fray/fracture in the wire. The only problem is these may have 2 wires in one wrapping. Meaning there is an outer wire around another casing for the ground wire or vice versa. If they are too expensive to replace then try to melt the rubber with a soldering iron and try to put a tiny bit of solder on the wire and put some heatshrink over the exposed wiring and heat with a hair dryer to secure it and keep from grounding.