I own two boats. One with a GPSMAP 276c and the other with a GPSMAP 376c. The 276c is connected to a GSD 20 and the 376c is connected to a GSD21. Both GSDs are connected to a Thru-hull Mount with Depth, Temperature and Fairing (Airmar B260) transducer. The 376c also has a XM antenna connected. Both of units have performed well for two years.
This year the XM radio has stopped working with an error message of "Check XM antenna". A few weeks later, the 376c now shows the wrong water temperature. With boats beside each other the 276c shows18 C (correct temperature) and the 376c shows 13 C. I will replace the XM antenna but I do not know how I can correct the wrong temperature reading. Is there a solution to this problem?