Both sides. Changed the bulbs and it doesn't work. Checked the fuse and it works as well (so does the horn, because it's the same fuse). What could be the problem??

(Oh, and I hope I posted in the right spot!)

 

I would inspect the brake switch that is switched on/off above the brake pedal.

 

Ms.Apes,

Yup, I'm going to concur with PA on this one and suggest that perhaps the Stop Switch Assembly is faulty on your Accord. This part is located above your brake pedal. I don't know whether you own a coupe or sedan model but the OEM part number for the '03 sedan is 35350-S5A-J04.

For your reference, it is depicted as ref #7 in the diagram below:

 

Are you having trouble with your cruise control?