Ford Repair: 2001 Ford Focus Overheating, duel overhead cam, repair garage

Question
My 2001 Ford Focus (Zetech, duel overhead cam) overheats in traffic when the a/c is off.  I first changed the thermostat and thought the problem was solved but after sitting in heavy traffic the car's meter started going into the red zone. I had it pressure checked, the plastic thermostat housing was cracked and replaced. It still overheated, so the techs changed the water pump and the top and bottom hoses. After all that it still overheats. This is making me crazy and broke. A friend of mine noticed the fan does not kick on normally but when I put the A/C on the both fans work beautify and the car cools down. He suggested buying a temperature control switch. After purchasing one we tried to find out where it goes. The parts department gave us, a kind of, scamatic showing where the part is suppose to go on the thermostat housing. Both places were blocked and there was no wiring harness to connect it to anyway. A tech, at parts, said my focus may not need that switch but I should replace the entire fan assembly instead. If that does not work he said it maybe the fan control box. I have seen this same overheating problem, on other sites, but there seems to be no answer. Up to now I am about six hundred bucks in the hole and if I do what the tech says I maybe spending another 700. - 900.00 dollars. This problem is killing me!

Thank you again for your help,

John  

Answer
Hello and thanks for the question...I'll try to help.
The fans are controlled by a multi-controller box in conjunction with a temp sending unit. It is most likely not the sending unit because you have not mentioned the check engine light being on. I would suggest that you have a repair garage check it out and diagnose it.
Erik