Facilitates flavin adenine dinucleotide (FAD) translocation across the mitochondrial inner membrane into the mitochondrial matrix where it acts as a redox cofactor to assist flavoenzyme activities in fundamental metabolic processes including fatty acid beta-oxidation, amino acid and choline metabolism as well as mitochondrial electron transportation. In particular, provides FAD to DLD dehydrogenase of the glycine cleavage system, part of mitochondrial one-carbon metabolic pathway involved in neural tube closure in early embryogenesis. {ECO:0000269|PubMed:16165386, ECO:0000269|PubMed:29666258, ECO:0000269|PubMed:35727412}. This is the function of ENSG00000164933 (SLC25A32, solute carrier family 25 member 32).