On the 2005 Chevy Avalanche, when the Blower Motor continues to run, even with the ignition off, on vehicles with Auto Temp Control,. the problem is going to lie in the Blower Motor Control Processor. It’s located under the passenger’s side dash, mounted to the HVAC housing, near the blower motor (very similar to a Blower Resistor, but “smarter” to accomodate the Auto feature). To gain access, remove the passenger’s side insulator panel (the panel right above where the passenger’s feet would be). Inspect the electrical connector for any loose, broken or melted wires. If the visual inspection checks ok replacing the control processor should solve the problem.
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