Assuming you are using RG6. Most likely the problem is the connectors not the coax. Unless coax was in an area where there was high heat. Normally coax lasts for years.
You can do a quick check for open or short on that coax line. Disconnect both ends. Put ohm meter on one end from center conducter to outer shield. It should be infinity. If that checks ok put a flashlight batter across center conductor to shield on one end. Measure voltage across the other end. If there is a problem check connectors first.
