Most ovens have two heating elements inside them. The broiler element on top of the oven turns on when broiling and it turns on and off during the bake setting. The baking element on the bottom of the stove will only turn on when the oven is set to bake. If your broiler works but your bottom element doesn't turn on in the bake mode or your oven never reaches the correct temperature, several things can be wrong.
Sometimes the electrical components in the oven can break so that they aren't able to transmit the right signal to the heating elements in the oven. The switch that ignites the broiler element may be working, but the switch that operates the other heating element may not turn on. The actual physical switch to turn the oven on may also be broken.
Broken Heating Element
The other heating element in the oven may be chipped, split or broken and, as such, it no longer works. You can easily replace this by unscrewing it from the oven and pulling it from the terminals. Press the replacement heating element into the terminal and secure it to the oven by replacing the screws.
The thermostat senses the oven's temperature and turns the heating elements on and off to keep a consistent temperature. If the thermostat is broken, it may be registering a high temperature and sending a signal to the heating elements to turn them off.
Broken Bake Igniter
Most often, if your heating element worn turn on, but your broiler will turn on, it is because the igniter is broken on that specific heating element. The igniter is the component that actually causes the element to glow. Generally, these mechanisms will weaken before they break. So, if you notice that the element only turns yellow or orange, rather than bright red, it is a sign that it is weakening and may soon need replacement.