Are these known for being an issue ? My front lax door one is inop , swapped over to drivers side and works fine in there , wiring ?

Does the passenger door activate the interior courtesy light?

No it does not !

That makes me think the issue is with the door switch, not the light.

Yeah, I've just read some mad blog on stripping it all down to fix it. Can the unit be replaced as one item ?

Wonder if this is what causes the chimes every time the key is turned ?

The chimes are just a reminder to put your seatbelt on.

Even with the seatbelt plugged in ?

I don't think it should with belt plugged in.

Even with the seatbelt plugged in ?

If your routine is "get in, fasten seat belt, turn ignition key to position 2 (and hence to 'start')" then the seatbelt reminder chime shouldn't sound.

{wonders} Do you also get an obviously spurious (because the engine is cold) overheating light flashing?

No overheating light, just the bongs regardless of seat belt being in or out.

No overheating light, just the bongs regardless of seat belt being in or out.

Fair enough; that was a question to eliminate a common cause.

What is the common cause ?