That's basically where I'm at. Dealer originally replaced tensioner and a couple belts which didn't correct the squeak, now they're thinking idler pulley which we're currently waiting on parts for. Unless it's some weird combination of belts and pulleys it seems that we're still at square one on this issue. I called Ford Customer Service today and they opened a file but won't escalate anything right now because the dealer is currently planning a repair. If the pulley doesn't solve the issue then they will look into it more. When I have more news I'll update, really annoying problem this is.