Review on High-Quality Blower Motor Resistor Complete Kit with Harness - Chevy, GMC Compatible - Silverado, Tahoe, Suburban, Sierra, Yukon XL - AC - Replaces OEM 15 81773, 89018778, 89019351 by Brandon Patterson

When installed correctly this product will perform extremely well. The response time is great and the fan speed is also responsive. I'm not sure if the stock wiring harness needs to be replaced, but if you do make sure you cut the wires ONE BY ONE. I cut all 3 at once and the high maxi fuse blew. Make sure your butt connectors are correct. Make sure the wire is fully inserted and wrap tightly around it. Dielectric grease on stripped wires and harness connections will also help. You can't go wrong with this stuff. Butt connectors are heat shrinkable. Take a heat gun, even Harbor Freight's cheapest, and heat it until the ends are close together. This protects the connections from dust and moisture. The product is wonderful. If installed correctly, there are no problems.