what does the key lock inside drivers door do?
Usually locks exterior access from the trunk lid or hatch. Deactivates the switch
I was under the impression that it disabled the fuel door switch.Turn it and see what no longer works.
On the 2000 model year Jetta example I examined, it locks access to the trunk from the exterior as well as the interior release. The intent surely would be to prevent unauthorized entry via the valet key. Hopefully you followed garageman's advice and simply tried it.
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