duffiel3,
Humminbird is not able to support servicing the Wide Portrait units any more. What you can do to check it though would be to fins someone else with a Humminbird unit and the your unit on their boat. It does not have to be another Wide Portrait as many of our current models use a transducer that will show whether the unit is working correctly. Just plug in the power and transducer buy hand (there were some changes in the parts that hold the connectors in place) and see if the water depth is shown correctly or not. If it is than the problem is in the transducer and you could possibly still find one of the older Tri-Beam transducers for it or use a QuadraBeam in place of it.

The temperature readout comes from a separate TG-W temperature Gauge. It may have become damaged and would need to be replaced.