I have a 2000 ford focus SE. Owned it for 3 yrs with no heat or a/c. The fan only turns on in the 4th position. I have noticed a regular loss of antifreeze with no obvious signs of leaking. When using a/c the little green comes on until put in 4th position. It will blow cold and immediately get hot. When using heat it does the same thing blowing hot then gets cold in 4th position. Positions 1-3 for both heat and a/c do not work. I need help! Been wanting to fix this, but wanted to narrow down what the problem could be before dropping a mass amount of money. Any suggestions would be amazing!