On a 2004 Audi A6, the turn signal flasher is typically located in the fuse box. The fuse box is usually found under the dashboard on the driver's side or in the engine compartment. To access it, you may need to remove a cover or panel. Refer to the owner's manual for specific details on the exact location and identification of the turn signal flasher.
The turn and hazard flasher relays are incorporated into hazard switch.
It's in the hazard warning switch. You need to replace the switch.
The turn signal flasher relay is located behind the hazard light switch, which you can access by removing the associated dash trim panel
1996-2001 Audi A4 1998-2005 Audi A6 1997-2003 Audi A8 The flasher is located on the dash above the radio, it is te same unit as the hazard switch.
Replace turn signal flasher
On a 1999 Audi A6 Quattro, the turn signal flasher is typically located in the fuse box, which is found under the dashboard on the driver's side. You may need to remove the cover of the fuse box to access the flasher relay. It's usually a small rectangular or cylindrical component that can be identified by its label or part number. Always refer to the vehicle’s owner manual for specific details and diagrams.
The flasher is right above the fuse box, pull it out, and replace it with a good one.
Inside the hazard switch.
The first and least expensive thing I would do is replace the turn signal flasher. If the flasher is weak, then it could act-up just as you have suggested. The turn signal flasher is a separate system then the four way or hazard flashers even though they use the same bulbs. Generally, the turn signal flasher (which simply plugs in) is located near the steering column but on your model I would suggest you purchase it from your dealer and ask them to print out the picture of the flasher which will show you it's location. I you. Mark
Check: Fuse Turn signal flasher Switch at steering column Bulbs
In the trunk.
It is connected to the back of your Hazard Flasher. I just had to change mine. About $65.00 to $70.00. Couple of clips at the bottom of front panel then it just pops out.