ok, i just had my duh of the day.
i went to autozone.com, entered your truck athis this is what i got:
On your 1999 FORD TRUCK EXPLORER 4WD, the FLASHER is:
FRONT SEATING AREA, DRIVER SIDE, BEHIND DASH, MOUNTED
ON STEERING COLUMN
"
In addition, they list the flasher at 12.99