After taking it apart and take out one of the LED near the center. I measured the junction temperature at three different currents after calculation this steel lead frame LED has thermal resistance of 445.2^OC/W.I then replace this LED electrically with another red LED to complete the electrical circuit.  I put the original LED back to its original location. The traces on the board that connected to this LED are cut and two wires are used to connect this LED to the outside.