Answer Hi James. The two inner(3/16" smaller) terminals are used for a biased pre-heater for the control. They are normally closed with an ohm meter. If they are open, then replace the control. The same for the outer 2 (5/16" terminals) are used for a predetermined heat range demand. These should ohm closed as well undenormal conditions. Hope this helps. Thank you. Read More... Answered by AppliancePartsPros.com | Thursday, July 14, 2011