Does anyone know where I can out find to replace an aux fan on a 1989 190e?

I would not call myself an auto mechanic - I can barely change the oil.

I took the car to a mechanic, and his quote is more than I can pay right now. I know I can buy the parts cheaper here than what he quoted. I did pay him for diagnosis, so I know what the problem is.

1. Fuse bad, replaced. It has since blown again.

2. One fan not at full speed, one fan not working at all.

3. From this, I assume the partially operational fan caused the fuse to blow.

Plan:

1. Replace fuse
2. Replace partially operational fan with new fan.
If I can get that far, then I know I can fix the second fan.

Questions:
Which fuse? (Tach and temp sensor OK)
Does anyone know where I can find instructions on how to replace fan?
How hard is it to replace? I can see only one screw and I know there must be more.

Thanks