Out of the blue, my truck seems to have lost the lowest 2 fan speeds.
Setting 3, 4 or 5 works fine. Never had this type issue before so I'm hoping someone who has, can steer me in the right direction...

I can only assume that the switch on the dash (well, actually behind the dash) is faulty. If that's correct, is it something that's available separately, or would I have to buy the entire HVAC control panel? I'm betting for either it's a dealer item only?

Where are you guys buying parts like this online?

Thanks in advance.

*** EDIT ***
Truck is "fixed". It was indeed the blower motor resistor. The harness pigtail was fine so I just replaced the resistor itself, with one from Advance Auto, and all is good. Took about 5 minutes to replace and it seems like the higher speeds actually blow air faster now as well. Thanks for the replies everyone.

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Mine lost 5 and I tried a buddy of mines new controls and it still didnt work. Still not fixed either.

 

After some quick Googling, it seems that this is a common issue, caused by a bad blower motor resistor. Looks to be a common part available at local parts store too....hopefully that fixes it.

 

Yes, it's going to be the resistor.

 

Don't go any buy one yet because GM has a special policy on thesse and it may be warranty. If your truck falls in this you can have it fixed for free.
If you would like I can check on it for you if you send me your vin.

 

Sent you a PM scooter k. It looks like Advance Auto has them for like 28 bucks, so it may not be best idea to have the truck sitting all day at my local stealership for that little bit of money.

 

If you get a chance take the heater box cover off and make sure your heater switch harness is not burnt. I just changed mine on my 06 switch went out and fused itself together....

 

As mentioned Above the problem is with the Blower Motor Resistor, also as mentioned above G.M. has a Special Coverage Adjustment for the Blower Motor Resistor,

.....G.M. SERVICE BULLETIN Special Coverage Adjustment,
Bulletin No.: 11046

Date: April 07, 2011

Subject: 11046 - Special Coverage Adjustment - Heating, Ventilation, and Air Conditioning Blower Not Fully Functional on All Blower Speeds, Inoperative, or Runs Continuously with the Ignition Off

Models:
2003-2006 Chevrolet Avalanche, Suburban, Tahoe
2003-2007 Chevrolet Silverado
2003-2006 GMC Yukon, Yukon XL
2003-2007 GMC Sierra
Equipped with Manual HVAC (CJ3) or Heavy Duty Heater (C42)

Due to part availability, owner letters will be released in phases starting with older model year first. Owners for model year vehicles not included in first phase owner mailing will receive an owner advisory letter.

The letter will inform the customer that parts are not yet available and that another letter will be sent to them when parts become available. A copy of this letter will be attached to the dealer message announcing this bulletin.

In the meantime, if a customer brings their vehicle to the dealership with the condition described in this bulletin, repair the vehicle using the parts called out in this bulletin.

Condition.......On some 2003-2006 model year Chevrolet Avalanche, Suburban, Tahoe; GMC Yukon, Yukon XL; and 2003-2007 model year Chevrolet Silverado and GMC Sierra vehicles equipped with a manual heating, ventilation, and air conditioning (HVAC) system (CJ3) or heavy duty heater (C42), the interface between the electrical terminals of the relay Resistor Module and the Wiring Connector that powers the module may be incapable of conducting higher current levels for sustained periods of blower motor operation. In addition, moisture and other contaminants may enter the fresh air intake plenum and contact the internal circuit of the module or corrode the terminals. Either of the above may cause the relay resistor module or wiring connector to overheat, resulting in one or more of the following symptoms:

- The HVAC blower may not function on certain or all blower speed settings
- A burning plastic smell or smoke may be present in the vehicle
- The HVAC blower may run continually with the ignition in the OFF position


IN VERY RARE events, if the above Symptoms are Ignored......A FIRE Could Occur.


SPECIAL COVERAGE ADJUSTMENT.......This special coverage covers the condition described above for a period of 10 YEARS OR 150,000 MILES (240,000km) whichever occurs first, from the Date the Vehicle was Originally Placed into Service.......Regardless of Ownership.

Dealer are to install a New Blower Module Connector......and the Repair will be made at No Charge to the Customer

.......IMPORTANT,
For vehicles covered by Vehicle Service Contracts, All eligible Claims with repair orders on or after April 8 2001 are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with Repair orders prior to April 8 2011 must be Sumitted to the Service Contract provider.

....VEHICLES INVOLVED,
Involved are certain 2003-2006 model year Chevrolet Avalanche, Suburban, Tahoe; GMC Yukon, Yukon XL; and 2003-2007 Model year Chevrolet Silverado and GMC Sierra Vehicles equipped with a Manual HVAV (CJ3) or Heavy Duty Heater (C42)

Inprotant,
Dealers are to confirm vehicle eligibility prior to beginning repairs by using the Applicable Warranties section in the Global Warranty Management system.

 

Thanks for the replies guys. It was indeed the resistor. I got one down the street at Advance Auto, for $28. Took all of 5 minutes to change out. In fact, took me longer to find the screw holes to put the cover back on, then to actually "fix" it...lol. My harness looked like new, so I just replaced the resistor and called it a day.

Thanks for the head's up, but as luck would have it, my truck is a 2002. You'd figure that since there is an obvious problem with this part on pre-2003 trucks that it would/should/could still be covered, but that would be too much like "right"...

 

Having a 99" I'm in the same Boat.....I agree with you rel3rd are Trucks should have been included, in the G.M. Coverage Adjustment.