Electric range not working

Oven controls not lit unless the light is on, either by switch or by opening the door. Even the lights that show the top burners are on don’t light unless the door is open. The oven light flickers. At one time there was an error code PO EO. We ordered a new clock/control part and replaced it. Still having the same issues, but the only code says Good. Not sure what to check next, if there are additional parts needed or if the control wasn’t at fault to begin with.
Thanks