To limit current draw, lights are wired in parallel. Lights in series would all fail if one failed.

If you hear "activity" by the fuse box when you play with it, you might have a corroded or lose connection that is causing a relay to switch.

Don't know about a body control module for lights and instruments. However, if your problem is limited to lights, isolate that circuit and check connections. Yes, even the switch...

John Stewart
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