Headlights problems of the 2010 Lincoln MKZ

Passenger side headlight low beam goes off with no indication does not matter whether stopped or moving. The only way to get it back on is turn lights off and turn back on but it does it repeatedly per trip. Does not make a difference if the car is moving or not. Took to dealer approx. Three times but could not find reason for problem. Dealer suggested to replace entire headlight component at a cost of approximate $3000. First the cost is extremely high, second I don't understand why there is no answer to why this is happening.

I was parked almost perpendicular to the curb (that was the way the parking spots were set. ) I put the car into reverse and was about to back out when I saw a car in my rear view. I quickly shifted into drive and put my foot on the brake. The car suddenly accelerated forward about a foot or more before striking a lamp post. There was extensive damage to the right front headlight as well as the bumper, grill and hood. The airbags did not deploy and there was no injury to the other 2-passengers. This was not the first time this phenomenon has happened. The sudden surge has occurred at least twice before. Both times when I was on a hill and put my foot on the brake to keep the car from rolling back.