Can my evap coil for my A/C be located under my house?

We are having some issues with the air conditioner keeping the house cool. We have cleaned the condenser coils and had someone check the freon. The only other thing we haven't checked Is the evaporator coil. Im not sure where to find it lol. I know we had a repairman come fix a fuse for us last year and he had to go under the house. Could it be located under there? Also, is cleaning the evaporator coil something I can do myself? I really can't afford to pay someone.