I'm trying to sort out an issues with a 95 Hot Springs Sovereign that my dad bought used about 5 years ago when he was living in my house and I was working away from home. In the first year it worked fine for about 3 months and started tripping the breaker instantly. The tub was drained and left because we were nearing winter and didn't want to be troubleshooting issues and risk freezing anything. The next year I noticed a loose ground wire, tightened that up and fill the tub to try it and again it worked fine for a while but eventually got to the point where the water was too hot, causing the power light to flash. Again, nearing winter the tub was drained and left. My dad moved out, I'm back home and have decided to try getting it working again. I filled it with water, and within a day the water temperature was up around 120 degrees with the power light flashing. I added cold water to bring it back down to around 100 so I could try the jets out and that worked fine. Within a few hours it was back to 120. The temperature control knob had no effect on the temperature, it always ends up around 120. I tested the control stat and high limit thermistors because those numbers were easy to find online and they both seem to function properly (reading about 4.5k ohms at 120 degrees). I need some guidance on what to test next.