What is..

[westbrookw]

the sensor over the drivers head? Darn thing started making noise like it is a compressor. I am not having any luck with this truck lately.

[WLPTMP]

where exactly is it?

[westbrookw]

Right above my head. I thought it was the microphone for the OnStar. Guess not.

[spudz]

the fix for that is to install a small sheet of foam behind it.. Its just rattling against the roof.

[BACKYARD88]

It's called an aspirator, it senses the vehicle inside temp for the auto A/C.

[spudz]

Copied from dealerworld. I never had to replace one yet..
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Subject: Buzz Noise From Headliner Above Driver - keywords air cover fan grill HVAC microphone onstar sensor speaker #PIT3511A - (11/08/2006)



Models: 2002-2006 Cadillac Escalade, EXT, ESV

2000-2006 Chevrolet Avalanche, Suburban, Tahoe

2003-2007 Chevrolet Silverado Classic

2003-2007 GMC Sierra Classic

2000-2006 GMC Yukon, Yukon XL, Yukon Denali, Yukon Denali XL

With RPO CJ2 or C68




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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Customers may comment that they have a buzz or vibration noise emanating from the headliner in an area that looks like a microphone or a small speaker.

Recommendation/Instructions:
The plastic escutcheon grill, which is round and about the size of a half dollar and located just above the driver to the left, is the interior ambient temperature sensor. The sensor is used in conjunction with the automatic HVAC (C68). On occasions, this sensor has been known to make a buzz or rattle sound. The sensor uses a small fan to pull air over the sensor. This buzz noise may be intermittent.

Although it may not be possible to alleviate all of the buzz or noise from this sensor, Engineering has found that if the sensor is installed incorrectly that it may bind and cause the fan to make a buzz noise. Remove the sensor and while doing so check for any binding. Reinstall the sensor and re-test. If the noise is still present, the sensor itself may be noisy and require replacement.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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© Copyright General Motors Corporation. All Rights Reserved.

[westbrookw]

Does anyone know how to replace this aspirator? Not really sure if it is worth $135.

[BACKYARD88]

Remove the left windshield garnish molding.
Remove the left center pillar assist handle.
Remove the left center pillar garnish molding.
Remove the left sunshade.
Gently pull down the headliner.



Disconnect the electrical connector from the inside air temperature sensor.
Partially remove the inside air temperature sensor from the headliner.
Remove the sensor grille from the inside air temperature sensor.



Remove the inside air temperature sensor from the headliner.
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Installation Procedure
Install the new sensor grille to the headliner.



Install the inside air temperature sensor to the headliner and sensor grille.



Connect the electrical connector to the inside air temperature sensor.
Install the left sunshade.
Install the left center pillar garnish molding.
Install the left center assist handle.
Install the left windshield garnish molding.

[westbrookw]

Thanks. Had to take it to the dealership to get the front diff seals and bearings replaced so I just had them do that also.