Radio Betrayal
In my previous post I indicated that the radio was connected to fuse 12 according to the wiring diagram. However, while fuse 12 was blown, the radio continued to work?!
When removing the radio from the middle console (no, it is not the Becker Radio Mexico Grand Prix anymore, although I still own one), you can see in the picture what a mess it is: wires have just been cut! :-(
Also, you can see in the lower right corner of the picture a red wire indicated by the yellow ellipse. This wire was an additional wire put in the car, on one side connected to the radio, and on the other side just wrapped around an arbitrary fuse. Eeks! What do we have fuses for, then?
The original wire had just been cut at the original plug for the radio and being insulated, so the hot ware was not in use anymore...
Solution
The solution in itself was easy. Not willing to change radio (now I have USB, BT and CD possibilities compared to cassette in the Becker radio) I just reconnected the original red wire to the radio and removed the additional red wire as that has become obsolete...
Radio antenna
It also explained why, after replacing fuse 12, the retractable antenna did not work at all...
With the mess created when the radio was replaced by the previous owner(s), all the wires have been cut, including the blue wire that goes to the switch to activate the retractable antenna... This wiring being disconnected, will make sure the antenna will not work :-(
No real need to fix this (now), as the current radio has been connected to an alternative antenna attached to the windshield.