the 7874 is a direct feed loom it has a seperate feed for battery and ground they either need to be wired into the battery or into the fuse box,
you cant really put them on to switch on with the ignition becuase it will always need a permanent feed,
your problem could be caused by a few things try making sure u have not connected the tele fone mute up, simple things check with a meter the power supply,
never use scotch locks they are sh*te, and remember cutting your alpine loom may mean invalidating the H/U warranty.
Tom