Diagnostic found that the secondary drain line would get water in it every time the system cycled off. This would trip the safety switch and shutoff the system. The current p-trap is not deep enough to allow the water to drain out the primary drain line. I spoke with the homeowner and she agreed to have the drain line rebuilt. I removed the safety switch from the secondary drain and installed it on the primary drain. I then dropped the p-trap 2inches and verified the drain line is leak free. Cycled power on the system a few times with no issues. I did also find the ducting is not sealed. The blower wheel is dirty and the outdoor fan motor is showing wear and tear. The system is operational at this time.