In which Sutta, Buddha wore cloth of dead body?
It is in  SN 16.11.


  ‘Your outer robe of patches is soft, Kassapa.’–‘Venerable sir, let the Blessed One accept my outer robe of patches, out of compassion.’–‘Then will you wear my worn-out hempen rag-robes? ’–‘I will, venerable sir.’ Thus I offered the Blessed One my outer robe of patches and received from him his worn-out hempen rag-robes.


However, the English translation doesn't mention that the Buddha wore a cloth wrapped to a dead body instead it just mentions worn-out hempen rag-robes. In the pali version it says the robe was paṃsukūlāni (rags discarded on the ground). 

The Buddha has obtained it from the dead body of a servant named Punna lying in the cemetery (this part is in the commentary). He wore this robe until he exchanged it with Maha Kassapa.