One problem related to alternator/generator/regulator has been reported for the 1998 Toyota Avalon. The most recently reported issues are listed below.
Electrical system shut down in traffic at the light, alternator was tested. Battery light stay on, lights dimmed out, lost speed. Had to get pushed out the road at a busy intersection in atlanta georgia on cleveland avenue. . Bought a second alternator, same exact incident . Once headlights are turned on at night, car looses total power. I had to drive five blocks at night without lights on ralph david abernathy blvd, atlanta georgia, even the hazard lights drained a brand new battery purchased 12/02/2018.