I only found three fans and all are working perfectly; Fan #1 for the lamp, Fan #2 for the DMD board and Fan #3 for the I/O board (attached to the cable card board).
When I disable each of these fans, the appropriate flash message appears for each fan 1,2 and 3 respectively.
I reviewed the Samsung service manual in great detail, and the manual references only two fans - one for the DMD board and the other for the lamp.
So, anyway I can remediated this issue "Check the Fan No. 4" issue?