tracking down a possibly grounded LIN-BUS and need to run test at splice SJ45. this splice connects to my sunroof module and rain sensor (not equipped) module and memory control (not equipped) module and ECM. any help would be appreciated.

 

SJ45 is just a slice. This is used to supply power to more than one item. You can try checking power at each to the connectors it supplies to and see what you get. JS45 supplies power on a red wire from C0961 pin 32 (central junction box) behind the lower glovebox to C0961 pin 2 (Sensor-Rain/Ambient light) behind the rearview mirror, C0784 pin 12 (Roof opening panel control module) in the headliner console above the rearview mirror and C2382 pin 8 (Memory control module) under the left front seat. All of this is assuming that the BCU will supply power to something that is not installed.

Help us help you. A little more information is needed before we can start guessing.
I have to ask. What problem are you having? Parasitic battery drain when it is off? Something else not working? Is there a code showing up?
Unless one of these unused connectors is touching the body, or a wire with worn insulation is grounding out, SJ45 should not be a focus of your problem.

Look forward to hearing back from you.

Jeff