My dim lights quit working. 2001 C70

I have searched the threads and found several people with strange electrical problems and a few with exactly the same problem I have but no clear identification of problem or solutions.

The is mention of the CEM (Central electrical module). Where is this located? What on line source is there for a replacement CEM? Is there a good way to test if the CEM is the culprit?

Also a thread with light switch potentially the problem - any comments or insight to this as the cause?

Also potential wireing issues. Maybe a service bulleting on a replacement harness but this seems for dim lights - not one completely stopped working?

Please help. Wife is really unhappy. My health and well being may be at risk!!!!