Been working through this lately, I replaced a couple of rear sensors, and 5v is what is shows flat when it is running right it seems. Now with the sensor replaced, the module seems to have fouled through that process, and that will be replaced. However, the actual answer from me and moral of my story here are that the sensor connection worked fine when some corroded connectors were removed, and then just connected straight in to avoid any potential future fouling. Hopefully the sensors last long enough to have that not be annoying to undo.