Old Lights and New Lights preachers both followed Protestantism. How did the two differ?

The two differed mainly in their interpretations of certain things and it was common for Old Lights to be associated with wanting to stick with the older ideas, while the New Lights would be people who would want to split from the denomination. It is also sometimes seen as the Old Lights followed certain Christian principles and the New Lights saw these principles as less binding and focused more on personal salvation.