I assume you mean, by morality, our discernment of good and evil, and our everyday choices to do good or evil. Then perhaps an effect of the Trinity is that we are better able to understand morality and act morally if we believe that the Father created everything and is the source of all good and all love, and we believe that the Son, Jesus the Christ, became man, suffered, died, and rose from the dead so that we might be saved from death, and we believe that the Spirit is now present to assist and guide us in our earthly lives as well as our spiritual journeys.
Of course there are people who are moral agents and live moral lives without such an understanding of the Trinity, but it is a truth that helps some of us.