There is a high limit thermostat switch that could prevent the bake element from heating even though the broil element will work. The bake element could be bad as well. A wiring failure or a failed electronic control board could also cause this problem. If you
shut off the breakers
to the oven (some homes have fuses that would need to be removed instead of breakers), you can check the resistance of the bake element with a volt/ohm meter if you have one. If you don't have a volt/ohm meter, you can normally get one from your local Sears or hardware store for less than $20. To check the element (with the breakers for the oven shut off), remove the screws in the back of the oven cavity that secure the element to the back wall. You may need to remove the oven door to gain better access to this area. Carefully pull the element into the oven cavity. Measure the resistance across the leads of the element. You should measure between 10 and 20 ohms of resistance. If you measure Ol (open load or infinite resistance) then the element is bad and will need to be replaced. If the element is okay, then you would need to pull the oven out of the cabinet and locate the high limit thermostat for the bake element. I provided a wiring diagram in the image below. This high limit thermostat may be on the top of the outside of the oven cavity or on the top of the outside back wall of the oven cavity. It will have red wires connected to it. There is another high limit thermostat for both elements that has black wires connected to it. You can check the high limit thermostat in the same manner as you checked the element with a volt/ohm meter. The high limit thermostat should measure near zero ohms of resistance. If it is open, then it will need to be replaced. If both of these components are okay then a wiring failure or a failed relay on the control board would be the likely cause of your failure.
These tips may help you diagnose and repair this oven failure. If you need more help, resubmit your question with additional details.
NOTE: Be sure that you completely disconnect electrical power to the oven before accessing internal components. Also, internal metal edges in the oven can be sharp. Protective gloves are recommended.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services