Flasher relays do work halfway and then stop and that is when the relay coils are failing.
If you adjusted the back lights to a brighter position, it should be draining more voltage from the relay if it is related. Maybe you can test if it happens again by readjusting back to previous to see if it happens. It could be related or coincidence.
Mabe you should check the grounding point for the relay. It is located at the lower left A pillar.
Monday, December 8th, 2008 AT 7:25 AM