Hello,
KitchenAid oven (w/o cooktop), convection, 3 wire, probably needs new thermostat?
It's heating and signals temp is reached, but setting for 350 is 180 inside, 400 setting is 250 inside, and 500 is 520 inside. (According to my lil oven thermometer.) Have had 2 cakes fail looking like too low temp.

A similar thread suggested multimeter and I'll have access to one in few days if that's helpful for checking before part ordering.

Advice please? Is it a thermostat I need to order? And can anyone suggest a part number? And when I looked online Whirlpool brand thermostats appeared, are the brands interchangeable?
Thank you.

Thank you. I'll watch the video and conduct the test and maybe pull the thermostat to match up the part.
The oven is from mid-90's. I rechecked the model number and it is correct, except perhaps the 5 is an S. But it is just a small plate inside the door and not real easy to read.
Now I have a pathway to repair. Thank you