The ground wire is just in front of your oil sump. Remove the undercarriage cover and you will see it. The horn grounds through the steering column through the rack and pinion.
The link below ha ...
did you ever find the ground wire on the steering column? I am looking for the same thing. Trying to figure out why the horn only works when the steering wheel is turn at a very specific angle.
I am having trouble getting my horn to work we any regularity on my '87 924S.
The horn will only work when the wheel is turned down to the left at about 30 degrees. A very small deviation of this ...
sadly I bumped up the front end of my 87 924S
Just wondering whether getting the parts from a 1979 924 will work? I need a hood, two lights, and the front bib.