Hi @beaualta ,
Could be any one of several components, thermostat, fuse, switches etc. Anywhere where the power goes through to get to all of the heater elements
Check the control board for any obvious damage i.e. burnt out or heat stressed components etc.
Here’s the ifixit [guide|99770] guide that should help.
If you spot any damage or even if not, post some close up images back here of the component side of the circuit board. Here’s how to do this [guide|21499]