There's actually a TSB for this:

April 28, 1998

Applies To: 1998 Accord - 2-door L4 thru VIN 1HGCG3...WA000039
- 2-door V6 thru VIN 1HGCG2.. .WA008389
- 4-door L4 thru VIN 1HGC...WA071280
- 4-door V6 thru VIN 1HGCG1...WA016316


Brake System Indicator Stays On

SYMPTOM

The brake system indicator does not go off after the vehicle is started and the parking brake lever is released.

PROBABLE CAUSE

The brake master cylinder reservoir cap float is saturated with brake fluid.

CORRECTIVE ACTION

Replace the brake master cylinder reservoir cap float with the one listed under PARTS INFORMATION