Pete--is the plug you are describing accessible without removing the battery? I read in the manual that there is a screen behind the "touch control" sensor (lower left in this photo), so I pulled that out--it is huge ... a fat tube maybe six inches long. No idea what the correct procedure would be to clean it ... I just wiped it off and put it back.
So, I guess I didn"t find the plug you mentioned. Do I need to pull out the battery and remove the battery box?