Thank you, WilliamM. There is no frost pattern on the freezer evap, and it is only cool to the touch. Freezer temp and defrost sensors were removed from the unit and resistance tested correct for both at room temp and in a freezing slurry. Their resistance was also correct when reinstalled and tested at the PCB with the wire harness pulled. Their voltage tested correct at PCB - connector and at MICOM.
I will remove the fridge cover and check frost pattern there. Do you think it’s necessary to remove the fridge thermistors and check their resistance? I did check their resistance and voltage at the PCB, as well as the ambient thermistor, and all checked out fine.
I’m puzzled. If the start relay (PTC thermistor) is not failed, why can’t I read continuity when testing (no beep), and why would its resistance read 1.25k ohms?
The compressor does shut off, but not because the unit has reached its set temps. I’m not sure how long it runs before shutting off, but it is hours. This happened on June 10 and hasn’t changed since. By the way, the OLP resistance is 0.3 ohms.
Thanks for your help with this.