Lloyd Williams returned from a five-game ban to score the try that sparked Cardiff Blues to their only Heineken Cup win of the season
The Blues had lost all five of their Pool 6 games and beating Sale boosted their hopes of retaining a top-six tournament ranking ahead of 2013-14.
Sale led through Tommy Taylor's try, but Leigh Halfpenny's three kicks gave the hosts a 9-7 half-time lead.
Aston Croall went over for Sale before Williams, then Michael Paterson struck.
Both sides were out of quarter-final contention before kick-off in conditions that had threatened a postponement.
Home fans responded to an-eve-of-game plea to help clear snow from the playing surface and were rewarded with a winning display after pitch inspections at 09:00 and 12:00 GMT.
But as they faced a whitewash, the Blues were determined to sign off on a high as well as bidding to retain their place in the European rankings' top half-dozen.
Established in 2007, the ERC European Rankings aim to reward clubs who consistently perform at the highest level in European competition over four seasons and separates the top six clubs in the pool stages.
Clubs earn between one to 11 points each season in the Heineken Cup and up to six points in the Amlin Challenge Cup to go towards their four season roll-over rankings.
The Blues rose from the bottom of Pool 6 to third as they condemned under-strength Aviva Premiership strugglers Sale to the bottom slot and picked up a rankings fillip in the process.
Having gone behind to hooker Taylor's early try and fly-half Rob Miller's conversion, Phil Davies' side had Wales full-back Halfpenny's boot to thank for keeping the contest finely balanced.
But after prop Croall went over and Miller converted it took Wales' Williams to put the home side on their way to victory.
He burst from a ruck before kicking ahead to gather and score and Halfpenny added the conversion to put the Blues back in front.
Williams then set up replacement lock Paterson's score.
Paterson won the line-out ball that allowed Williams to break free near the touchline and the lock was in support to take the scoring pass.
Halfpenny again converted to take his match tally to 16 points.
VIEWS FROM THE DRESSING ROOM
Cardiff Blues boss Phil Davies:
"That was good today. We got the result and we haven't finished bottom of the table, which is just reward for all the hard work we've put in.
"We've played some good rugby during the first five games and not had many rewards for it. That was a pleasing way to finish.
"I felt we played some good rugby in the first half, but we did not quite get that last pass away to score.
"We said at half-time if we continued playing with a bit of patience we could break them."
Sale head coach Bryan Redpath:
"I thought the referee disallowed a perfectly good [Sale] try.
"We had our opportunities. We had loads and loads of pressure and the chances to win.
"But there were a couple of defensive errors we lapsed on and gifted 12 to 15 points."
Blues: Leigh Halfpenny; Alex Cuthbert, Owen Williams, Jamie Roberts, Harry Robinson; Rhys Patchell, Lloyd Williams; Sam Hobbs, Rhys Williams, Scott Andrews, Lou Reed, James Down, Josh Navidi, Andries Pretorius, Sam Warburton (capt).
Replacements: Jason Tovey for Robinson (74), Nathan Trevett for Hobbs (74), Kristian Dacey for R Williams (57), Michael Paterson for Down (41).
Not Used: Bourrust, Jones, Hewitt, Hamilton.
Sharks: Cameron Shepherd; Tom Brady, Jordan Davies, Mark Jennings, Charlie Amesbury; Rob Miller, Will Cliff; Aston Croall, Tommy Taylor, Vadim Cobilas, Tom Holmes, Kearnan Myall, James Doyle, Richie Vernon David Seymour.
Replacements: Mark Cueto for Jennings (49), Nathan Fowles for Cliff (67), Ross Harrison for Croall (59), Marc Jones for Taylor (67), Eifion Lewis-Roberts for Cobilas (49), Richie Gray for Myall (74).
Not Used: Cruse, Cipriani.
Referee: Peter Fizgibbon (Ireland)