passenger side high beam light stays on when cold

When the car has about 26000 miles the passenger side light start to have issues. When the wheather was a little cold, i can't even attemt to flash the high beam on and off, because the passenger side high beam stays ON all the times. When the wheather warms up i didn't have the issue and i thought that was something temporary. When it gets colder again, the problem is back. I took the car to the Ford dealer, and they want to charge me about $150.00 just to take a look at the light, because the car just passed the 40000 miles and there is no longer covered. (I'm paying about $30.00 monthly for some kind of extented waranty) However the advisor told me that i need a new headlight complete which will cost me over $700.00 include labor. I rather to use the car with the deffect head light, and i have decided this Ford to be the last Ford i will drive. The reason for my decision is this problem, but also other past problems, and the bad service from Ford dealers.