2003 Sojourn HP @Home, Dimension One spa; third control pack, p/n 1782-1000 installed Dec 2010. Symptoms: set point is 102F, actual water temp per Thermapen is 102F, display shows 32F, pump/heater pulses on for a second then shuts off. Did reset, let it cool to below 97F, then turned back on breaker. Same symptom returned. Part-monkey action to date: (actually per recommendations from easyspaparts.com) - replaced upper display, p/n 01560-345-6C. Wired it up, let it hang outside of tub cover for a few days, no similar symptom. Installed/caulked it in, worked fine for 5 days, then same symptoms returned. Then, got new temp sensor, 01560-79; plugged it in hanging over the edge. Worked fine for several days. Installed it in, with new wall-mount assembly/oring, repacked insulation around sensor. Worked fine for about 5 days, then same symptoms returned: display shows 32F, pump/heater cycles on for a second every minute or so, set temp is 102, water temp is 102F.
Ideas?