No power to oven but there is power to grill. How can I fix?

BOSCH HBN13M551B Double Oven. No power to oven or red oven indicator light. Initially problems with the oven power selector switch, difficulty in changing oven temp. Eventually switch broke completely and had to turn power off to the oven. Found that the switch coupling had broken and replaced it but no power to main oven. The second oven/grill is working OK.
What do you suggest we check or replace next?

Trevor
June 2009