A faulty control board or thermostat can cause an oven fan like that on the GE Profile electric range to run constantly. All GE Profile electric ranges are convection ovens, and a convection motor that shorts out can also cause the motor to constantly run.
Newer ovens have a digital control board that determines which functions turn on. Since ovens have different settings for different cooking temperatures, there are a number of relays that can short out and cause components to run constantly. If the oven continues to produce heat while running, the control board may be at fault, although this problem can still occur even if the oven is not warming up.
Ovens also have an integrated thermostat that controls when the stove produces heat, and these thermostats are typically linked to fans as well to keep the oven from overheating. A faulty thermostat can cause a fan to continue running even if the oven has cooled down. A short circuit can also cause this problem.
All of GE's Profile ovens are convection ovens that contain a convection motor. If the motor has a short circuit, the fans continue to run. Convection ovens continue to warm up even if the convection motor stops working, so diagnosing this problem can be difficult.