I had the same problem before but now the problem is gone. The indicator is so sensitive that a slight change in output would trigger the switch. WHat I did is to turn on all the exterior lights then stand far from the car to check the brightness of each bulb. I discovered that one taillight was slightly dimmer than the others. I replaced the bulb but tat the same time, cleaned all the terminals and more importantly, I made sure that the contacts were all ok. You may need a long nose pliers or srcew driver to bend the contacts a bit. I also used sand paper to "scratch" the contacts.
Hope this helps