2007 Sundancer 40 Water Temp not working

[crizz]

2007 Sundancer 40 with Cummins and factory dual E120s and no DSM with a Systemview SC5000 screen. I believe the Airmar smart transducer DT800 should supply water temp to the systemview, but the readout always reads the same temp. Depth works great.

Should I go straight to replacing the transducer or is there anything else I should check?

Strangely, air temp also always reads the same as well.

Thanks for any help!
Eric