I would like to know as well. I've searched the web and can't find them. Would hate to replace the entire unit at several hundred dollars for a failed $25 part.
sorry to hear that - there are two sensors. On mine, the one that goes to the gauge has one wire and the one to the ECM has a two pronged plug. they are both on the thermostat housing. looking on line at diagrams and what I could find when i was doing research, showed some used the single...
Was having the same issue with my 5.7 TBI - after researching I changed the Temperature Sending Unit - there are two, one for the gauge and one for the ECM - replaced the one for the ECM. Works like a champ.
You can get the Mercruiser one on amazon...