Probably the heater element has failed but I would verify that before ordering. A simple continuity test is all you need to verify.
If the heater is fine but a limit is open then be sure and check for lint and/or a loose blower wheel.
To get into the machine:
Remove the screws to the door hinges and get the door out yer way.
Grab the goal posts on both sides at the top of the dryer and yank the
front panel towards you lift it up and out the way.
Remove the brackets that secure the top.
Get the front shroud off. Remove the drum. Check all components for continuity.
Click pics to enlarge:
Note: The bottom is the innards the large tube on the right holds the heater element.