Hi Kathy,
If you lost power to all the rear lighting at one time, I doubt it has anything to do with the harness unless it was cut.
I attached the exterior lighting schematic below for you. However, I have a feeling the problem will be found in the TIPM (totally integrated power module).
The TIPM is basically the fuse box under the hood. I've seen many issues over the years with the connectors to the TIPM. Simply put (at least in my mind) they placed too many pins in the connectors. As a result, the pins are very small and prone to damage, corrosion, and breaking.
I'm not sure what point you are at with the wiring harness, but if it doesn't take care of the issue, let me know and we'll check for issues at the TIPM.
Take care and let me know what you find.
Joe
See pics below.
Images (Click to make bigger)
SPONSORED LINKS
Saturday, March 18th, 2023 AT 11:40 AM