No Power with Key Off to Radio and Clock

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  • Thank you everyone for putting up with me. Here is my next issue:


    When I turn off the key, there is no power going to the clock and the radio. When I turn the key "on", 3 volts goes to the radio and the clock.


    This means that every time I turn the key back on, I have to unlock the radio and reset the clock. :(


    The schematic is not very easy to follow (especially if you don't speak or write German). Does anyone know where the source of 3 volts is for these two systems? For some reason, the 3 volt signal goes away with the key "off".

  • There is nowhere a voltage of 3V DC in the car.


    The radio should stop playing when the key has turned to zero but the memory should remain.


    The memory for the radio and power to the clock comes from fuse F21 (wiring schematics page 2 path (which is seen at the bottom) 80)

    The clock is in path 85 ant in path 79 You see a termination with cross reference to path 139 and at the top of path 139 the line continues to the radio.


    Because there are some other things which are at fuse F21 it is possible, that there comes some voltage back or it comes from the ignition plus of the radio..


    Please check the fuse F21 - not only visually because sometimes You do not see if these kind of fuses are damaged - check it with a measutring device or change it.


    Please also check with a measuring device in the fuse box when the fuse is removed if on one of the contacts insidew the box the 12V are existing.


    If Yes and if the fuse is OK - I only see the possibility that the immoboilizer brings this problem.


    The problem is in such a case, that it is not possible to say much more, without looking at the car and measuring and comparing with the wiring schematics.

    Unfortunately my next business trip to the states is far away.

    Das BMW Cabrio ist eines jener sachlichen Transportmittel, das grundsätzlich offen, vollgetankt und mit dem Schlüssel im Zündschloß in der Garage stehen muß - für alle dringenden Fälle.

  • Georg,


    Thank you so much for this info. I had already checked all of the fuses, but did it again, because of the above info. And yes, Fuse 21 was blown!


    I don't know how I missed it the first time.


    I definitely owe you a beer now.


    I hope you can wait: I don't get to Germany too often.

  • One more thing I forgot to add above: Everything works great now.


    Back to working on the cracked body panels.

  • As i wrote before: Sometimes You do not see when this type of fuse is broken.


    It is very sad that the cover of the fuse box isn't a little bit higher, because from E-T-A exist resetable fuses for cars Klick

    The problem is - these fuses are higher than the originals and so there is not enough space under the cover.

    Das BMW Cabrio ist eines jener sachlichen Transportmittel, das grundsätzlich offen, vollgetankt und mit dem Schlüssel im Zündschloß in der Garage stehen muß - für alle dringenden Fälle.