Check Brake lamp Fuse 24.
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=1252216&page=2&view=collapsed&sb=5&o=31&fpart=1
Edit. Also check other fuses as noted by 1996 Ford CD Manual.
PINPOINT TEST A: SHIFT INTERLOCK SYSTEM DOES NOT RELEASE OR LOCK PROPERLY
�² A1: CHECK SUPPLY FUSE
�² A2: CHECK FOR SHORT TO GROUND
�² A3: CHECK POWER SUPPLY FROM FUSE 30 (7.5A)
�² A4: CHECK INSTRUMENT INTERFACE MODULE GROUND
�² A5: CHECK POWER SUPPLY FROM STOPLIGHT SWITCH
�² A6: CHECK STOPLAMP OPERATION
�² A7: CHECK GEARSHIFT LEVER SWITCH INPUT
�² A8: CHECK INSTRUMENT INTERFACE MODULE FUNCTION
�² A9: CHECK WIRE BETWEEN INSTRUMENT INTERFACE MODULE AND GEARSHIFT LEVER
�² A10: CHECK GEARSHIFT LEVER SUPPLY
�² A11: CHECK FUSE 23 (15A)
�² A12: CHECK CIRCUIT 14 (P/W)
�² A13: CHECK POWER SUPPLY TO GEARSHIFT LEVER
�² A14: CHECK FUSE 34 (7.5A)
�² A15: CHECK CIRCUIT 29 (O/Y)
�² A16: CHECK GEARSHIFT LEVER
�² A17: CHECK CIRCUIT 29S (O/W) AND 29S (O/Y)
�² A18: CHECK GROUND 31 (BK)