I have same problem, its a 2001 ford focus 1.6 zetec, the fan has been making squeaking noises for ages on and off, and yesterday it just decided to only work on the highest setting no 4, I have read another thread on here about replacing the heat sensor or something. I can get the glove box out but the blue sensor?, is impoposible to get to, also the fuse box is very difficult to get to as its in a sharp metal housing so cant get to the back of it to check the fuse, Am I right in saying if I replace the heat sensor it wiould probably just blow again as the blower is seized up??. Would really like a step by step instruction with pictures of how to sort this out as It is really pissing me off going to work with the blower on 4 all the way making a stupid screaching noise.