The 98s had a safety recall on the headlight switch. Probably
did not affect all of them since 98s were made for a long time.
So, you may or may not be affected. You can call a
dealer and give them the cars' VIN number and the can do a
lookup of the records for all recalls on your car.

Here is the info on the headlight recall:

Recall 99V235000: Headlamp Switch Malfunction

Vehicle Description: Passenger vehicles. Operation of the headlight switch, over an extended period of time, can result in inconsistent operation of the switch. Driver's could experience a loss of visibility, increasing the risk of a crash.

Dealers will replace the headlight switch.

Owner notification began September 15, 1999. Owners who take their vehicles to an authorized dealer on an agreed upon service date and do not receive the free remedy within a reasonable time should contact Volvo at 1-800-458-1552. Also contact the National Highway Traffic Safety Administration's Auto Safety Hotline at 1-888-DASH-2-DOT (1-888-327-4236).