Australia must win in Dunedin to retain hope of reclaiming the Bledisloe Cup for the first time since 2002, having slumped to a 54-34 defeat in the opening Test, the margin of which flatters them having trailed 54-6 early in the second half in Sydney last Saturday.
Coles was one of only three personnel changes to the side that destroyed Australia last Saturday, with lock Scott Barrett coming on to the bench for Luke Romano.
Footage clearly showed Williams wobbled on his feet but wasn't taken from the field for a head injury assessment.
Aaron Smith remains in Steve Hansen's good books too, despite revelations of the No.9 being dishonest with the coach past year.
Haylett-Petty's return for his 18th start was expected after he made a bright start to his test career previous year and he will play on the right wing on Saturday with Henry Speight switching to the left.
Replacements: 16-Tatafu Polota-Nau, 17-Tom Robertson, 18-Sekope Kepu, 19-Rory Arnold, 20-Lopeti Timani/Jack Dempsey, 21-Nick Phipps, 22-Reece Hodge, 23-Curtis Rona.
'I got into a bit of a dark place, ' he said. Damian McKenzie remains at fullback where he will make his second test start while Ben Smith and Rieko Ioane are on the wings.
"Whilst we were very happy with the way we played for periods of the game in the first test, there were also moments where we weren't so crash hot", Hansen said, referring to the final 30 minutes of the game when the Wallabies scored four unanswered tries. 'However, this is a new week and we're well aware that we'll have to be better in all areas of our game and we've concentrated on those areas we want to improve.