The parts diagram does not show a resistor / control module for the front blower. It does for the rear/auxillary blower.
The blower actually has 3 wires on the connector, Black, Red, and a light blue (i think) -- dark and hard to see.
I believe the resistor functionality has been replaced with a Pulse Code Modulation (PCM) signal to control the ground side of the circuit.
On the rear unit, there is a separate, resistor/module that recieves the PCM signal and switches the ground on and off to create the variable speed of the blower.
Since the front blower has the third wire at the connector, I am assuming it incorporates the resistor function into the blower.
If it is, as I believe, a PCM signal, i probably cannot get a good reading with a probe or multimeter. But will be trying both tomorrow. Will also be checking the 12v and ground wires for continuity.
I have also eyed those parts you listed, and compared with the GMpartsonline diagrams. Looks like the Denali is a little different.
I'll update on the voltage checks tomorrow.
Thanks for the post.