I have an 05 6441. In the last two days the stop light on the left side of the dash has been coming on. Initially it was only at idle, but now I have to push the throttle up to 11 or 1200 rpm before it goes out. No other lights come on along with this. Fluids are good (levels and quality). I wondered about alternator, but the battery light hasn't come on. Any thoughts or help would be greatly appreciated.