Ever since I've had this car the headlights flicker at times. It seems like it happens a lot when I use the brakes. When I come up behind a car at a stop sometimes they seem to be flickering very rapidly, too fast to count the flickers. Then it stops. And repeats, usually when braking. At times they flash briefly as if I have used the highbeams for a split second.
Dealer states there is nothing wrong with the electrical system or lights, but they also didn't see the flickering occur.
Is this a common problem? I've had the car 3 years now and put over 20K on it with this happening most of the time when I use the headlights. I don't drive much at night so haven't bothered with pursuing the problem after the dealer couldn't find any problem. Any ideas?

 

Mine did this for a while on on side after I first bought it. I figured it was either the bulb or the ballast. I changed the flickering bulb to the non flickering side and it still flickered.
This meant it was the bulb. Bucked up $120.00 for a new bulb and problem solved. The new bulbs look a different color as they do change with time.
Sounds like both of yours need changing.
I would try that first as the ballast is a little more than $120.00 and a lot more expensive and difficult to change.