Have just fitted a CISBO parking sensor kit to my 2002 ducato motorhome. Installation went well but on selecting reverse NOTHING have 12 volt at the plug when reverse selected but nothing happens. The mains plug has three leads one is to be conected to the ignition if the van is CANBUS as far as i can tell 2002 was before canbus so have not conected that wire. Before i get in touch with the supplier any one have any ideas.