If you have auto climate control (ACC), the system uses a "blower control module" for fan speed control. Usually when the module fails, it will be in the “no run” mode or, where the blower motor runs continuously. (Even with the key off). It looks like you got lucky, yours failed in the “no run” mode.
The "blower control module", is located on top of the fan box and under the fuse and relay section on the firewall. (Passenger side) It has two wiring connectors and three screws holding it in the box. (See pics below)
You can get a new module from most GM dealers, for about $150.00. Also, check with your local salvage yard, (usually about $50.00) It is such a common problem, they usually keep one at the front counter. Be careful when buying from a salvage yard & try to get the same part number as the original. (The part number will be on the module). GM made four or five different modules that look similar; however, they do not have the same part number, number of wires, or the same functions.
(Some are three pin and others four pin) In addition, you can purchase an aftermarket module from Advanced, O’Reilly and NAPA for around $100.00.
| This is the module
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| This is the location of the module
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