Just the Facts: Two or Four? That is the question! There are several questions concerning two General Motors Blower Motor Resistors. The resistors below are used on the same vehicles, with respect to year, make and model. To make things more complex, the Standard RU571 requires the original resistor mounting plate be discarded and the replacement unit bolt directly to the blower case. The GM replacement resistor is not the same as the OE part. Use the information below to help decide which resistor each vehicle requires. Standard RU571 GM 89019088, Delco 15-81086 Discard the existing mounting plate to install the replacement unit Mount this resistor directly to the blower case This resistor has 4 mounting holes In most cases, vehicles without a console will use the RU571 Standard RU371 GM 89019089, Delco 15-81087 This resistor mounts with no modifications It has 2 mounting holes In most cases, vehicles with a console will use the RU371 and may cause failure of the anti-lock braking system to operate safely and properly. Application Data 06-02, 00-99 Cadillac Escalade 06-02 Chevrolet Light Truck Avalanche 06-99 Chevrolet Light Truck Fullsize Pickup 06-99 Chevrolet Light Truck Suburban/Fullsize Blazer/Tahoe 06-99 GMC Light Truck Fullsize Pickup 06-00 GMC Light Truck Suburban/Fullsize Jimmy/Yukon GM TSB Information GM TSB 05-01-38-012C concerns the failure of the OE blower motor resistor and the subsequent damage to the vehicle harness connector. This TSB recommends replacement of the vehicle harness pigtail when replacing the blower motor resistor. We offer this replacement pigtail as our Standard S-916. Please refer to the actual TSB for further details View our 21st Century Tune-Up® video video Back to Just the Facts