Having just launched and first "test" sail of the season on Sunday, I notice that my temp gauge has NO reading! I have a Westerbeke 13 A on my '86 Cal-28. It's running fine but what would the steps be to isolate the gauge problem....could it be the sender, the gauge itself. etc? I've checked the connections on the back of the gauge and they are fine. Anyone know where the sender is located? Thanks...Steph