One problem related to wiring has been reported for the 1998 Audi A6. The most recently reported issues are listed below.
On may 31 2005 while driving smelled a burning odor. Then, smoke came from air vents, and smoke got worse. While speaking w/ 911 flames began to come from the air vents. Fire appeared to come from the air vents. Vehicle was operating normally before the fire broke out. There was no warning or codes to owner's knowledge. It was unknown what caused the fire. Owner believed it was an electrical fire. The fire department had a hard time extinguishing the fire, and were unsure as to the cause of the fire. A police report filed. Car was serviced regularly and records were available. The car was moved to a storage facility behind a gas station. The insurance company took possession of the vehicle, and considered it a total loss. Audi contacted the owner about an investigation. There were other recalls but nothing about this vehicle.