I wanted to know if fan limit is on the board on Goodman model GDS8115CNA?

Switch should be up somewhere on the burner box.It is mechanical and cuts fan on when box get hot. Should be two wires on it.

Are you asking about a fan control, or high limit? Fan control may be built into the control boad. High limit will always be separate from the board as Hot Corn Bread mentioned and will trip from overtemps causing the blower to run constantly and the gas valve to shut down.