Attention: Please be sure to check the appearance ( include pin quantity and installation hole quantity ) of the blower resistor on your car and whether OE part number is the same as the blower resistor you bought! Because the blower resistor you bought is suitable for the same vehicle as the other 3 different blower resistors Manual AC Control: This AC blower motor resistor you selected is a resistor module for manual ac control Application For Chevy: 2003-2006 Avalanche 1500, 2003-2006 Avalanche 2500, 2003-2006 Silverado 1500, 2003-2006 Silverado 1500HD, 2003-2004 Silverado 2500, 2003-2006 Silverado 2500HD, 2003-2006 Silverado 3500, 2003-2006 Suburban 1500, 2003-2006 Suburban 2500, 2003-2006 Tahoe Application For GMC: 2003-2006 Sierra 1500, 2003-2006 Sierra 1500HD, 2003-2006 Sierra 2500, 2003-2006 Sierra 2500HD, 2003-2006 Sierra 3500, 2003-2006 Yukon, 2003-2006 Yukon XL 1500, 2003-2006 Yukon XL 2500 Application For Cadillac: 2003-2006 Escalade ESV, 2003-2006 Escalade EXT Replace OE Number: 89019088, 973-405, 973405, 15-81086, 22807123, 1580582, 1581086, 89018308, 89018596, RU571, JA1582, 4P1449. Do check your car model in the "amazonconfirmedfit" in the top left corner before ordering Working Principle: The blower motor resistor is an important component in an automotive heating,ventilation and air conditioning systerm. The ac blower motor resistor is responsible for controlling the blower motor speed. When you adjust the speed of the fan in the car, you are actually adjusting the current that the a/c blower motor resistor allows to reach the fan motor. The higher the fan speed setting, the greater the electrical flow allowed through, and the faster the fan motor speed Advantage: All Marsflex a/c blower motor resistors meet or exceed OE design and performance. Strict testing procedure and superior materials that provide maximum strength and durability. The quality, durability and reliability of all products are backed by over 50 years of excellence in experience. It is sure to easy installation and safe operation Warranty: 1-year warranty. Package includes 1 ac blower motor resistor and a wire harness. Do not hesitate to contact us if you have any doubts or queries Marsflex Blower Motor Resistor 89019088 2003 2004 2005 2006 for Chevrolet Chevy Avalanche Silverado 1500 2500 Suburban Tahoe, for GMC Sierra Yukon, Blower Resistor 1581086 with Manual AC Control