We just installed a used Frigidaire electric convection double wall oven in our kitchen. After finishing the electrical connections I turned on the breaker and came upstairs to find the upper cooling fan running. It hasn't turned off yet, despite the oven not being used at all, except for a 3-5 minutes short warmup to verify the heating element was working (several hours ago). The model number is FEB398WECD. Hoping for some assistance in tracking down the cause of this issue, whether it's a defective thermostat, bad control board, or something else entirely.