02' Envoy

[MJBaldwin]

Alright guys I know you are all very smart on here and looking for a little advice. My wife and I just bought this vehicle has about 85k miles on it. Got a decent deal despite the year. She went down to the cities this weekend and is now hearing a very odd noise coming from what she described as the vents. She said it started maybe around Alexanderia (we are in Fargo/Moorhead) and really noticed it once she got to her brothers in Albertville. This noise she said is on when the blower is off as well as on? Any ideas that I can have her try to fix this issue?

Thanks In Advance

[LightningBG]

hmmm. What did the noise sound like?

Any performance changes besides the noise?

The envoys are known to have some issues with the vent doors and the actuators, but I'm guessing that isn't the issue if it happens when the blower is off.

A possible culprit could be the fresh air intake blend door.

This is a post from another site. Does your issue seem similar?

Quote:

Fresh air blend door makes grinding sound 75% of the time

I've searched around here and can't find this discussed.

Its not the vent blend door that I found a sticky on.

My issue is the fresh air door thats behind the glove box. When I'm riding down the road, majority of the time, it makes a sound that kinda sounds like rwaaba rwaba rwaba ........constantly. Its kinda grinding slipping rubbing sound that doesn't change with blower speed. I thought it was my blower acting up. I removed the glove box and took the blower out and discovered the following.

When the fresh air damper moved to either closed or open position, its like the actual motor keeps turning, so the damper reaches a stop, and the motor keeps turning and the shaft is apparently rotating inside the sleeve of the damper and keeps turning making the rubbing sound above. You can hit the recirc button and the damper will swing the other way (momentarily stopping the noise), and the motor keeps turning and makes the sound still that direction.

Its as though something should be telling the motor that the damper has reached position, stop rotating. But it doesn't.

Sometimes however, it will stop rotating, and of course the sound stops.

Do I have to tear the whole dash out to replace that actuator? And whats the part called? Any idea if it might be a stop sensor thats supposed to tell the motor its reached position? Or is it based on internal motor resistance? ie, that shaft to damper should be a hard tight fit with no slip and not allow the motor to keep rotating the shaft?

Any ideas?

[Macgyver55]

A description of the sound would help a lot.

I have run into a couple of Envoys and Trailblazers that had secondary air injection pumps that would intermittently run that made a whirring noise that might be confused with air vent noise.

[Jeremy airjer W]

Or, if the check engine light is on its possible the fan clutch is stuck on full speed. The sound hood change with engine RPM and sound like a low pitch roar.

[MJBaldwin]

Thanks for the replies guys we brought it back to the dealer and it was the motor than switches it from driver side air to passenger or both. That motor was either burnt out or that diverter was broken.