describe the ministers wicked impulses as he returns home in scarlet letter

This more or less takes place in Chapter 20. First, Dimmesdale meets an aging deacon of the church,

"It was only by the most careful self-control that the former could refrain from uttering certain blasphemous suggestions that rose into his mind, respecting the communion supper."

If that wasn't enough Dimmesdale then meets an aging woman of the congregation who loves nothing more than to hear the truths of scripture from her pastor. That is about as good as things get for a Puritan pastor. Instead of making Jesus proud, Dimmesdale lies,

"As the great enemy of souls would have it, could recall no text of Scripture, nor aught else, except a brief, pithy,and, as it then appeared to him, unanswerable argument against the immortality of the human soul."

To top it all off Dimmesdale feels the urge to shake hands with a drunken sailor and then a known "witch" smiles at him! These wicked impulses are of course a culmination of a lifetime of adherence to his ultra-repressive occupation but poor Dimmesdale doesn't see this; he just suffers in silence at his "wretched" existence.