Intrigued by this one? :scratching_chin:
The Purple/Yellow (P/Y)wires are the +12v feed from the Horn Relay in the fuse box. That feeds +12v (P/Y) & ground (black) into the rotary coupler (pins 3 & 4) to the Horn switches and the Cruise Control (if fitted).
Fitting a push switch in to connect the P/Y wire to ground will make the horn sound - Howardo's fix.
The Alarm CCU does the same thing at the other end of the P/Y wire to make lots of noise when the tea-leaf tries to nick it (the P/Y wire has three ends!).
The only +12volt feed to this wire is via the horn relay in the fuse box - nothing
shown going anywhere near the audio stuff? :crazy:
There is a pair of wires for the audio remote going via the rotary coupler (pins 5 & 6) but they go back to the head unit and are sense wires not power feeds?
Even the earth (ground) connections are (supposed to be) separate. The Audio uses the same one as the aux power socket and other 'heavy' ground feeds and the horn switches use a separate lighter 'relay' ground point?
Even the Rotary Coupler diag below leaves off the connection from SJ31 to the Alarm CCU - so what chance have we got? :frusty:
Intrigued
BUT as I have found from my delvings into the actual FL wiring, what they did with the wiring does not always follow the Rave !!
Changing the audio
shouldn't do it but I would like to know why it does.
My guess would be something to do with the black (earth) wires and how they get back to the bodywork? (it may not be as in the diagrams - horn return via the audio connectors perhaps?) Won't hurt to try a temporary clean (good) ground connection into the Rotary Coupler black wire for the horn buttons with the new audio fitted and see what happens?
Let us know if you do get it working.
