What would cause a 2001 QX4 headlights to turn off all of a sudden at night?

The headlights "turn out" at night when it is below 45 degrees and the car is not warmed up yet after the blinker "resets" to center when making a turn after about 78K miles. This is a power surge problem with the high beam function of the blinker arm that shuts the ballast off just long enough to loose one or both headlights. You can turn them off for one full second and back on they will be fine until the next turn or when the motor comes up to normal operating temperature.