I have a Simpson electric oven with stove top elements, and one of the burners will only cook at the highest level, I cant figure out how to change it, any suggestions?

You need to change the "Simmerstat", take the model number to your local electrical parts supplier/parts counter at your local stove retail shop that sells Simpson stoves and ask for one for that model, make sure you get the right one for the position as some control a single element and some control dual elements.

*** TURN OFF THE WALL SWITCH AND ENSURE NO POWER IS APPLIED TO THE STOVE BEFORE PROCEEDING ****
Remove the upper back panel of the stove. Swap wire for wire of the old simmerstat to the new one, remove the knob from the old Simmerstat, undo the nut securing the simmerstat in the oven control panel and discard, fit new one, secure, fit knob, fit back panel, turn on wall switch and test.

Some countrys/states require registered electricians perform this task on electrical appliances so you must ensure you can do this legally before you start and take the relevant safety precautions and don't electrocute yourself.