Ye, brake light switch/stop light switch (as webtech calls it).

 

ill check out some schematics for you if you still cant figure it out after messing with the switch.

 

I Got the plug for the top of the tranny, reverse lights now work

http://www.rdtiburon.com/index.php?showtopic=15789 (fuse box breakdown). I'm going to look at all fuses again, and swap them all out this time. I'm paying specific attention to #3

 

Ye #3 is the one that controls lights.

I had same problem as you after my turbo install fyi, brake lights don't work but running lights did. My brake light switch was bad.

 

what do you do if the switch is bad? how much was a replacement? I haven't tried the plug yet. fuse was fine

 

Uh, you might be screwed and have to go to Hyundai. I went to Autozone and ordered one and they sent a clutch pedal switch, and the part # was right so you can't get one there. Its about $12 for one though.

I ended up pulling one off my parts car.