Went to fit the new later type E36 steering wheel (airbag) to my non airbag 94 car. Mine has the carbon switch and single wire, the old slipring has a brass backing which earthed when the horn was depressed.

The newer wheel has a blue and brown wire - have tried connecting the brown one to the wire going into the carbon switch, no joy. Earthing the wire causes the horn to work successfully. Can't find much on this online - anyone do this previously?

Looking at how its all set up, it should work - initial thought is a damaged slipring on the new wheel.