Raoul
Many of my grommets are in lousy shape (or non-existent) as well.
Although grommet kits are cheap and available, I have decided to put them on the longer-term list for when I paint the car again. In the shorterm, I am more cautious with car washing -- not to flood the "bonnet" area. And, since mine is primarily a sunny-day car, I am not overly concerned.
Only thing I can add about the mystery cable is: does your tachometer work? It sounded a bit like that cable.
Cheers
James
63 230SL