I've checked my 1993 Sonata manual (U.S.) It doesn't show a brake lamp warning lamp. It shows the fuse in question as fuse #3 in the dash fuse box. Check the kick panel under the left side of the dash for the fuse box. Also be sure to check the bulbs and the brake light switch on the brake pedal.
Okay, I take that back. It appears the DRL unit has the ability to illuminate the BRAKE warning lamp using the same circuit as the parking brake and fluid level sensor in the master cylinder.
My manual does have a DRL schematic (for Canadian vehicles). Here's what I can figure:
pin 1 -- red -- applies ground to illuminate brake warning lamp, receives ground from parking brake lever switch.
pin 2 -- white/black -- privides ground to headlamp relay, energizing headlamps.
pin 3 -- unused
pin 4 -- red/white -- receives power from fuse 11 in dash fuse box
pin 5 -- yellow/red -- receives ground from light switch when in "park" or "head" position.
pin 6 -- yellow/green -- provides ground to tail lamp relay, operating tail lamps.
pin 7 -- black -- DRL unit ground
pin 8 -- white/green -- provides ground when alternator is not charging (tells DRL unit whether car is running).
pin 9 -- brown -- DRL unit grounds this wire, causing either dim headlamps (low and high beams in series) or low beams, depending on status of head lamp relay.