here is a thought for you. After looking closely and doing some investigative work this is what I found. Without the tail lights or marker lights on, the turn signals work correctly with no flashing from any other lights other than the turn signal being used. With the tail lights on, if I turn either turn signal on they work correctly, but all the other lights dim when the turn signal element flashes then brighten again in between flashes. I do not think the secondary elements in the turn signal that is not being used, is flashing, it just appears to be flashing because it is brightening and dimming because of the juice that is being pulled from the flashing bulb. I am testing this with the car not running and key on so I don't know if this happens with the car running. No exhaust yet and the sound is unbearable. Is this normal?