AlaskanTubMan

I have a 2003 Sundance Marin 850 tub, and I can''t seem to figure out what is going on with the temperature sensor that sits within the filter area. The tub will work as expected for several hours, and then go into watchdog mode with the 4 dashes. When I look at the log data, everything is normal except the temperature sensor high was at 125F, even though I know the water was nowhere near that temp. I put in a new temperature sensor, and the exact same thing happens, even when the water is only at 85F. Just to be clear, this is the temperature sensor that sits next to the filter, and not the high temp limit sensor within the heater. the high limit temp data is normal. I noticed that the wires were resting on the circulation pump, so I thought maybe the heat/magnetic field might be causing the sensor to misread, but even after making sure its far away from all pumps, its still having the problem. other info- the board was replaced at some point, at least 5-7 years ago, though I'm not sure exactly when since it was before I owned it. All the capacitors look good, as in I didn't notice any swelling or leakage. any ideas on how to troubleshoot? I'm hoping I don't need to buy and install a new board, but thats all I can think of.