Determining if a trait it autosomal or X-linked?

So I have access to a pedigree, and have also done a gel electrophoresis for a family, looking at the ear wax gene. A few of the males in the pedigree had three bands on their gel, which corresponds to a hetero-zygote genotype. If the trait is x-linked, CAN a male even be a hetero-zygote, since they only have ONE X chromosome? (Or does this mean that it must then be an austosomal trait?) Because by doing a pedigree ysis, you cannot determine if the gene has a autosomal recessive or x-linked recessive mode of inheritance.