My understanding of approximants is that they are produced without the tongue coming into direct contact with any of the articulators in the mouth, which is true for /w/ /r/ and /j/. But /l/ is classed as an approximant even though - at least in my accent - the tongue pretty much directly touches the alveolar ridge. The manner sounds the same as a fricative to me.
What is it that makes /l/ a lateral approximant, rather than a fricative?