I have an 89 Mustang with a cooling fan that wont switch on. The car gets hot during low speed driving. The fan motor isnt the problem since I jumped it and it ran. So I went and got a new tempature switch (the one in the bottom of the intake manifold) and it still wont turn on. In my chiltons manual it says that the fan is supposed to turn on at 221 degrees. The only way to get the fan to work is to ground it out, but then it runs all the time.