The top surface of the dryer is too hot.
In most cases when the top of the dryer is getting to hot, the issue would be caused by a air vent that is clogged up. You can disconnect the vent from the back of the unit and check to make sure that the top does not get hot and if it does not then the vent is block. Also check the venting inside the dryer and the blower wheel.
The dryer warms up but it seems like it doesn't get hot enough. I'd like to be able to get it apart so I can test the heating coils and the thermostats and thermal fuse. How do I expose these parts?
To access the heater and thermostats you will need to lift the main top, remove the front panel and remove the drum. To lift the main top there will be a spring clip between the front panel and main top. You will push in on the clips and lift the top. Once lifted there will be a screw on the inside that holds the outer panel to the front. Remove the screws and disconnect the belt. Once it is loose, remove the front panel and take the belt loose. Once loose you will need to lift the tub out to check the thermal and replace necessary parts.