Heat is intermittent - can I access the control board by removing the touchscreen and stereo unit?

POSSIBLY 'alldatadiy.com' (small fee$) , may have diagnostic tests/procedures outlined. touch screen probably has a 'self-diagnosis' mode , but I don't have that info myself. Unless you are very skilled electronically , I would not recommend disassembling anything at this time , may never get it back together.