Two problems related to brake light have been reported for the 1998 Chevrolet Lumina. The most recently reported issues are listed below.
The two main brake lights no longer come on when brakes are applied. The 3rd brake light in rear window still works. Both bulbs were checked and even replaced to no avail. The turn signals flash at a high speed, unless the turn signal lever is manipulated with a slight pull/push. Checked several internet sites on the problem, and it seems it may be the directional signal switch. Not sure if this is a major fix with specialized tools if the problem is in the steering column.
1998 Chevrolet Lumina - brake light failure (center light is ok, both taillights don't work). Very common, according to web searches of the problem. Related to turn signal and/or emergency flasher switch (if these are physically 'jiggled' brake lights temporarily work).