Wiring diagrams are split up into their corresponding category so sometimes they can be difficult to locate. I.E. The wiring diagram for a brake switch input at the ECM from the ABS system may be found in the ABS category instead of the Powertrain Management category. Or, in this case, the brake input or output for the Cruise Control will be found under that category instead of Powertrain Management.

Also, to address a much earlier but critical question, the data communications in these late model systems uses a twisted pair wiring configuration that requires a 120 ohm terminating resistor at either end. As you can see in one of your diagrams posted earlier the ECM in this vehicle contains one of the terminating resistors, but in order to communicate with the modules the other end of the twisted pair must have a terminating resistor as well. I don't know about operating the ECM without a BCM, but I was under the impression that it was not possible because the BCM serves as a gateway module for all module communications and more importantly it is a power-moding module that manages the power mode for all modules on both the high-speed and low-speed LAN networks. This means that the ECM and TCM do not wake-up with a switched +12v power source, rather the BCM sends a wake-up command over the high-speed LAN network. I do not know how these modules behave without the BCM connected to the data lines. Yes you may be able to communicate with them, but will they wake-up and sleep properly ? If the modules don't switch to sleep mode, their rate of power consumption when awake would most likely drain a battery overnight.