Signal works fine till I turn the headlights on then the left rear stops blinking and the error message comes up on the dash. Its as predictable as death. after it stops blinking I can switch the headlights off but still have the error message and the light still won't blink..UNTIL I can switch the ign. key off and back on and it works fine again till I hit the headlights again...I've checked the light sockets and the plugs at the back...mixed up with the headlight switch some how...anyone had this issue before?