2004 Trailblazer, perfect fit. Remove two screws on bottom dash panel below glove box(7mm socket). Blower motor resistor is behind blower towards firewall. Two screws to remove it(5.5mm socket). Remove two wiring plugs, power in and at blower. Cut plug off connection from power in, three wires. Splice into wires of five pin connector on new resistor. Plug connector into blower first, wire would not reach when I installed resistor first. Install new resistor, test, and install dash panel. Blower was not shutting off with car, but it does now. FLAWLESS!
HVAC Blower Motor Resistor Connector (84645) by Dorman®. 7 Way Female Terminals Connector. Dorman’s Blower Motor Resistor promptly returns your vehicle’s heating and cooling system to its original peak performance. The long-lasting design resists thermal fuse failure, overheating, and burnout. This product also boldly withstands the condensation that typically causes corrosion in resistors.
The blower motor resistor is mounted to the blower motor. You can change it by removing the lower foot trim on passenger side of vehicle, or for even easier access, In this tech article I will highlight how to replace the blower motor and the blower motor resistor separately.