I wish I knew. I have a 2002 Grand Cherokee that is doing the same thing.
Bad turn signal flasher?
replace flasher for for turn signals
Flasher is faulty.
It contains two relays, one for hazard lights and the other for turn signals. The one for the turn signals is defective and must be replaced.
a bulb is bad and must be replaced
Check: Fuse Turn signal flasher Switch at steering column Bulbs
My research to date finds that the turn signals and hazard signals are controlled by a common relay. That relay is behind the hazard relay switch. My 2002 Audi A6 has the same symptoms you describe, and I will be removing the hazard switch to get at the relay for replacement. Good luck.
Check the fuse
1999 Audi a6 quattro, How I fix the problem when the turn signals don't blink, but hazard lights work well?
It controls the windows and turn signals
most likely would be a bad turn signal flasher