It appears that my car has the Canadian DRL function set, but something is amiss with the control of the dash lights. The dash lights function correctly except for when the light stalk switch is set to "off" with ignition on, in which case the dash lights are off instead of on.
The stalk switch works normally for the DRL.

After reviewing the wiring diagram, I am at a loss to discover what might be at issue unless it is an atypical light stalk failure, and I can find no mention of such a failure elsewhere although it seem that weird things can happen with this car.

The car has no error messages or scan codes set.

And I thought that my 928 was a wiring horror show! 🤪

 

As you've seen looking at the wiring diagram the dimmer lighting circuit is far too complex for it's own good unfortunately.

Assume you've checked all the fuses all you can really do at this point is test the lighting stalk switch is giving the correct signal to the dimmer module according to the wiring diagram (ground when lights on, not connected when off) and then check the outputs of the dimmer module are doing what you expect.

That might help isolate where the fault is and at least you will then know what makes them come on.

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