HVAC is making rattling noise

It sounds to me that your belt or tensioner is worn, if the noise goes away when the ac is off then it is just the belt slipping, it takes a lot of power to run the compressor and if the belt is worn it most likely slipping on the pully when you engage the clutch.

Test the electrical circuits ! Manual HVAC or automatic HVAC ?
Do you know the difference ? Heater / A/C blower motor electrical control diffrent . Manual has resistors an a relay for different speeds , automatic has a blower motor control module .Free wiring diagrams here http://www.bbbind.com/free-tsb Enter vehicle info year , make , model and engine size . Under system click on HVAC ,then under subsystem HVAC controls will pop up . Click the search button , then the blue links . First off you need to know what system yours has , manual or automatic.
GMC Yukon HVAC Blower Motor Won Turn On
Blower Motor Problems Auto Repair Help

It appears your fan itself burned out. When a field coil of an electrical fan burns out it usually makes a lot of smoke. The noise could be something that fell in there that stopped the fan from turning freely. I can imagine it heated up under the strain and burned out.

When you restarted it was burnt out so hence no noise and no fan.
The smell of the smoke should also be clue. Electrical field coils burning has an awful soury type of smell.

The 1992 was prior to Buick putting cabin air filters in so there is not a possibility it is clogged. So more than likely your blower motor is going bad or your fan control switch is bad. Does this problem occur with heating as well as AC? Does it change if you switch between blowing on floor, face, window(defrost) If it doesnt change based on location of blow and type of air temp then I would start by turning fan on high and placing head (ear ) against dash in center of console area. Have someone turn fan knob from low to high with engine OFF...After goign from low to high and back a few times you can see if the blower motor is responding to signal from switch. Listen for a whine, squeal, rattle, or humm. A whine or Humm would indicate a bad blower motor... Squeal or rattle a bad squirrel cage/fan blower blades. If you hear no noise and no perceivable change in blower speed/noise then its possible your switch is bad. Unfortunately the only way to definitely diagnose either is to pull the switch from dash and use multimeter to test for voltage change and for blower motor to pull dash. There is a digital control unit for your car as well. Although rare sometimes the wires on this can loosen or it can go bad. But since you didnt state teh fan wasnt working at all and you are getting cool air, that woudl be teh last thing to check

the bearings in the blower motor could be bad. in which case you'll have to change the motor. or the fan has come loose from the shaft andmight be fixable. or something got inside and is rattling around. removal of the motor will be necessary in any cases. go to autozone.com to veiw repair guides for you car. register and enter your car. and select vehicle repair guides from the list on the left. then heating and cooling.

That "speaker looking thing" above the drivers head on the headliner is a part of the climate control system.

Here is the GM bulletin regarding it if you are running in to these issue:

Document ID# 1639237

Subject: Buzz Noise From Headliner Above Driver - keywords ac air aspirator cover fan grille HVAC interior microphone sensor speaker temperature vent vibration #PIT3511 - (03/29/2005)



Models: 2000-05 Cadillac Escalade

2002-05 Chevrolet Avalanche

2000-05 Chevrolet Silverado, Suburban, Tahoe

2000-05 GMC Sierra, Yukon, Yukon XL, Yukon Denali

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

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

If you pull out the glove box you will find the in cabin air filter, you probly want to replace it

SOUNDS LIKE YOU ARE LOW ON FREEON YOUR SYSTEM NEEDS A CERTAIN AMOUNT OF PRESSURE TO TURN ON AND OFF SO THE FAN TURNS ON WHICH IS NORMAL BUT THE CLUTCH ON THE A/C COMPRESSOR IS NOT TURNING ON 1/2 -1 POUND NEEDS TO BE ADDED TO YOUR SYSTEM

there should be only one fan and its under the hood on the passenger side firewall. it takes about 30 minutes to change and its the only motor you will see of that side,its held in by three screws and a plug.

first, check steering fluid level, then check fan belts. if thats not it, your power steering pump is probably bad.