I havre replaced the broiler element and had the timer/clock repaired but still cannot get both burners of the broiler element to get hot - only one of the burners works. Service man suggested the unit may be stuck in "low" heat for broiler and "hi" heat for broiler would engage both burner. Thought this would be controlled through the timer/clock. Had that repaired and I still do not see how you move the broiler unit from low to high. Help!!!