Religious Pluralism sets aside conflicting truth statements and instead focuses on universality and unity of all religions. Religious Relativism on the other hand resolves the conflicting truth statements as being manifestations of divine/human relations. That is to say, religious relativism sees the truth as having been interpreted by certain people at certain time from the perspective of their own cultural upbringing. For instance show a Hindu who knows nothing of Jesus a common picture of Jesus and he will interpret it from the context of his understanding. So different people in different places can quite easily see and experience the exact same thing, but the interpretation and understanding will be different.
To go with a cooking analogy... Pluralism is like taking a few different soup recipes and keeping only what is common to all. This may give you a very nice soup base, but it will lack much in style. Where as Relativism will allow you to enjoy your soup of choice as it is or even different unique flavors of each soup according to your changing desires.
It is obvious I have a bias toward religious relativism. I have a strong preference for rich traditions, high ritual and the subtle theological distinctions where the change of a single word can utterly change the meaning. However I only enjoy it in so much as they can be practiced without being disrespectful toward other traditions.
Yes even though I am an eclectic mystic Pagan, with smattering of Buddhist philosophy and other eastern religious studies... I do still enjoy the occasional Mass and attending Gregorian chant when the opportunity arises.