On my zafira b horn itself works even though it looks as though its been rescued from the titanic i ran a direct 12 volt cable to it and it beeps :) the connections on the horn were just spade conections so looks as though its had a different horn in the past i changed the spade connections as they were rused to hell im only getting 3-4v dc then the horn button on the steering wheeel is pressed the relay is clicking away ok ive tried to short across connections as you have shown in this great clip im getting the same readings back at my multimeter looking at the condition of the wiring itself its very tarnished inside the conductivity will no doubt be poor im guessing this could be the problem ? i might even just run another feed into car dash put a push to make horn button and new wiring via a relay to the existing horn as the wiring loom looks a pain.

Hi we have a vauxhall zafia and had a stereo fitted by Halfords no problems horn worked and so did other controls on steering wheel but months later everything stopped and when trying the horn on steering wheel it turns up the stereo is this something I can do myself or do you suggest taking to main dealer Thanks in advance John and claire