Roper model # rs5agxnq00. My roper frig was manufactured in 2005, we notice that it now runs for a

Question

My roper frig was manufactured in 2005, we notice that it now runs for a while and then stop working until you manually turn off the temperature to 0; leave it for a while and turn it back to 4 or 5. I suspect it is the timer for the defrost that might have goone bad. anyhelp will be appreciated.