window failures

My Ford F150 XLT 4Door Truck with only 46,000 miles, has experienced failures with all four side electric windowns. Motors have all failed within a 1 year period. Had first window repaired at Valencia Ford, in Valencia, CA. The cost to replace the "window regulator" was over $400.00. Since that time the remaining three windows have experience the same failures. I wrote to Ford and complained, and was promptly emailed with instructions to take the truck into a Ford Dealership for inspection before Ford could take any responsibility. Truck was taken to Sunrise Ford dealership (place of purchase)for inspection. The dealership representative stated that all three "window Regulators" needed to be replaced, and they would pay for the first window, but that I would be responsible to pay $617.63 for the other two. I found this to be outrages, and unacceptable. This is clearly a faulty design of Ford Motor Company, which they are unwilling to rectify. I for one will never purchase another Ford product of any kind.