After troubleshooting the lack of blower fan airflow I determined the problem was the blower fan control module. This part receives a pulsed signal from the head unit controller using a Brown wire. This output of the control module will directly control the blower motor via the purple wire. I wasn’t getting shit out of the module.

The control module is one of those non-serviceable components. It’s covered in some sort of high pot material for protection.

After installing the replacement part Delco 16061602 I performed a test. The new part completely fixed the lack of fan blower control. I glad it wasn’t the actual control module itself. I’ve had to replace that component on my 1989 C4 Corvette and it’s not an easy task within the small confines of the interior layout.