fishbuster

hey guys we recently purchased the Lowrance X-98-DF and this is a sonar fishfinder and its a duel frequency sonar and it locks on the bottom good so far. but the temprature gauge sometimes doesnt not work and sometimes makes the depth and/or speed not work also. but when we unplug the speed cord from the temp/transducer w/ the temp everything works except the speed obviously. has anyone had this problem before and if so how did you resolve this problem? thanks for the info.