A couple of things. Make sure if you replace it yourself be sure to use an AC Delco part. Some of the aftermarket resistors won't even last a day or two. Also check and make sure the AC drain hose isn't plugged. If it is plugged moisture backs up in the blower housing and cause corrosion on the wire terminals.
KMGZ400, Did the dealer say why it wasn't covered under warranty? Was it because the VIN# didn't fall within the recall? I am assuming you are talking about your 03 Silverado.
Below is a G.M Service Bulletin, Regarding the Problems with 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) Important, Dealers are to confirm vehicle eligibility prior to beginning repairs by using the Applicable Warranties section in the Global Warranty Management system.