My Westinghouse 688 freestyle wall oven?

The problem is that you do not define your problem...

Is it that the light and the fan are on at the same time?
Is it that the fan and the light both stop?
The dial you mention - is it a temperature setting or a function?
If it is a function dial what position do you select?

Your question - as written - is a bit of a mystery
What is wrong with what?
What does the oven do that it should not do?
What does the oven not do that it should do?

Good Luck...
July 2016