2000 Cadillac SLS Blower Motor not working

At the blower control module, do you have battery power on the orange wire pin B, and ground at pin A. The fuse is in the rear fuse block, under the back seat cushion, on the drivers side. From there it requires a pulse width modulated signal from the instrument panel module(which I believe is the control head). Is that the temp control module you are referring to?

I do have power and will have to check for ground at the module. I have power but no ground at the fan motor connection with the fan control switch on (any position) so likely no ground at the module. I believe you're right, it is the IPC I was referring to (the parts department called it a temp control head). I have lights on the IPC so I figured there is a ground at least to that. The fan may have a dedicated ground however. In looking at the wiring diagram for this car it appears that HVAC runs through the DIM but I'm not completely sure. If so, that is the one major component I have not replaced. It also appears GM uses a constant power and then runs the unit by completing the ground at various resistances.
Beautiful car, just plagued by lots of electrical problems and a leaky trunk.

It is ground G201, listed as located under the front of the rh door sill plate. It is the blower control module ground. You could supply a ground by feeding one to the back of the connector terminal A, that will tell you if it will work. It could be that the wire is open somewhere as well. The blower module supplies voltage and ground to the blower. On your trunk leaks, often times weatherstrip solves that, assuming it is clean rain water and not road wash.. Look for ater coming in under the weatherstrip. Another area is seams void of sealer in the taillight cavities, or the corners where the rear quarter panels meet the rear of the rear wheel wells.