Flutter/rattle sound from front passenger side behind dash?

[Paultu1985]

I recently purchased a 1995 Buick LeSabre Custom from a the original owner - a 94 year old lady who bought it new off the Buick lot here in the Kansas City area 20 years ago. The car is immaculate in every way and only has 80K miles on it. I've always loved the Buick Park Avenue/LeSabre run from 1991 to... 96? and have owned several. So back to the question...

Behind the dash on the passenger side (sounds like it's behind the AC vent, more or less) is a strange fluttering/rattling sound. When I hit a bump in the road, it will squeak a bit louder. The sound can be heard with the car in park, at idle, with the HVAC and blower turned OFF. I've watched all those old Buick-produced videos on YouTube for eliminating squeaks and rattles - but I don't think they ever described what mine is doing. Any ideas? I'm stumped on this one... and it's really annoying as the car is so incredibly quiet, except for that one squeak that over time drives you insane.

 

[MelsRegal]

Since you hear it with the vehicle standing still I would suspect the blower motor. The motor may operate even with the switch in what you call the off position to provide constant ventilation.

 

[AviatorFrank]

Sometimes a piece of debris will get sucked into the blower cage and rattle around in there. Even a small piece of paper at the high speed it turns will unbalance it enough to cause vibration, but if the blower is truly off and not just on low and you still hear it, it's likely one of those infernal actuators/damper door control units we all have had issues with. Don't know in 1995 if they were electrically or vacuum-operated, but either way that's likely the cause. Have fun!

 

[Paultu1985]

Pretty confident it's not the blower motor. One, the blower motor is located towards the floor - not up higher in the dash. Two, the sound does not change in volume or pitch with the blower on high/low/off - it's still present. Appreciate the suggestion though - any other ideas?

- - - Updated - - -

Sometimes a piece of debris will get sucked into the blower cage and rattle around in there. Even a small piece of paper at the high speed it turns will unbalance it enough to cause vibration, but if the blower is truly off and not just on low and you still hear it, it's likely one of those infernal actuators/damper door control units we all have had issues with. Don't know in 1995 if they were electrically or vacuum-operated, but either way that's likely the cause. Have fun!

I don't like your suggestion. 😛 Can you please come back with one that's easy??? 😉

That makes sense. I think they're vacuum operated... even more fun. Let's hope that you're wrong, but that makes sense.

 

[AviatorFrank]

LOL I hear you on that. My 2005 is rattling too and it's the center actuator. Just keep reminding yourself - it's a comfortable car, it's a safe car, despite the problems . . . 🙂