Morning all. Following the info here I have wired a td5 speedo into my 300tdi.

I have wired all the pins in plug A with the exception of those for the alarm LED and ECU.

when I plug it with ignition off the mileage display shows. Is this right ? If so what is the difference in operation of the switched 12v and perm 12v? And yes I have double checked that the ignition feed is switchable. Thanks.