Blower fan motor 2002 Nissan Sentra

The Heater a/c, blower fan on my Sentra only works on speed 4 It will engage the A/C on 1,2,3,4 but the blower will only run in position 4 Any help?

The answer is the same as this one.

http://community.cartalk.com/posts/list/477810.page