Horn issues - any thoughts?

[DHDamo]

Hi guys, horn was becoming inconsistent now (after pulling the dash apart to solve heater problems) it doesn't work at all. My multimeter tells me that the wire in the middle of steering wheel is live. I think there may be an issue with the horn 'button' itself. It's got a wire on the back and part of the spring part presses against the steering wheel/column (it appears) to complete the circuit. Cannot get it to work. Any ideas?

[Fylnn]

The horn earths through the steering column.  With the multimeter check the steering column is earthed.  There is a series of wires that bridge the earthing across the uni joints.  Check they are all still in place and earthing.  The horn ultimately earths through the steering column.

[DHDamo]

Thanks Flynn, all of those were in place. Did some further digging and checked the steering column earth in engine bay - disintegrated. Problem solved and horn working again. Cheers.