1999 Ford Taurus After Collision

[quote:bb3550d21a="lindseywhite"]Noises problem
1999 Ford Taurus 170478 miles

I rear ended another driver a few days ago, and since then, my car has been making a loud noise only when my heat/air is on. It sounds sort of like when you put a baseball card a bike tire, but extremely loud and electrical sounding under the hood. The heat and air work fine, it just makes that horrible loud noise, and it goes away once i turn the air/heat off. What could be wrong with it?[/quote:bb3550d21a]

Something has fallen into the heater assembly, and is contacting the fan blades. Most likely something that fell into the defrostar outlet or an a/c register many moons ago - like an air freshener or a piece of paper or a pen, or a business card that was laid up on the dash and long forgotten. The collision jarred it into contact with the fan.