My '88 300SE seems to have an ignition switch problem...

After starting my car, I must play with the key in order to get my AC blower to work. I usually turn my fan on hi and turn the key back just enough to get the fan motor to kick in. Once on, the fan stays on - but this occurs every time I start the car.

My question is... what needs to be replaced, and how difficult is it for a person with minimal tools and one who does not like to spend hours upside down under the dash. Thanks!!