Todd;
I had the same problem with my 1998 marin tonight. flo/106/sn3/ice etc. i followed the lead from the temperature sensor (I had to replace it last year) and found that although the leads were inside the black multi-plug that was in the board, the negative had somehow vibrated loose. As you are looking at it the temp sensor leads are the right most as you look at the pigtail assembly. The wires should be black and red, top to bottom. They should be encased in a gray telephone like wire. Here is the fix:
If your tub is older, you should get a new temp sensor. You can install this yourself. YOu will have to drain the water below the sensor which is located in the filter compartment. It is a little stubby thing. It has a plastic nut on the backside and comes with a new washer. When you replace the new one you will have to splice the wires into the existing leads as most temp sensors for our age models are generic now.
Tinning with solder is best for the repair but a standard wire crimp splice will do.
Make sure that the red and black wires are snug in the black clip. You will see that if you pull on them and they come out they are not secured. They have little brass barbs that are supposed to grab and hold. Mine seem to have vibrated loose. I don't know of a way to test the temp sensor. Check
http://spapartsnet.com/Electronic-Temp-Sensors
If you need please email me and I can send you pix if my directions are confusing.
Todd
