1995 Altima - Heater Blower Fan

Hi guys,

I need your help once again. My 1995 Altima is a 2.4. Liter 4 cylinder with 110,000 miles. I went to turn on my heater fan the other day and it would not work in the first three positions of the switch but worked on the highest speed onlly. I have checked the fuses for the blower motor and they are both okay. Are there different fuses or relays that control the lower three fan speeds? I don't think the switch would go bad in three postions all at once. Any ideas?