done it, instructions here:
http://shufti.wordpress.com/2010/10/06/dual-horn-relay-and-wiring/

as Mark D. said, you do need some molex connectors or else use
salvaged pigtails as I did.

Dual horns with relay was a vanagon option, in Europe at least.

alistair

On 15-May-11, at 6:41 PM, Edward Maglott wrote:

> Well, I got my horn button fixed so that I can beep while going
> straight.  Then thought I would get a louder horn than the old stock
> one that is a little anemic.  I got a dual hi-lo horn kit and set
> about installing.  Hooked them up, but no beep.  After a lot of
> troubleshooting, it seems that they take enough extra current that my
> system can't get them honking.  When I fixed the horn contact ring in
> the steering wheel, I bent the finger that touches the rotating
> ring.  there is not a lot left of that finger to make contact.  I
> wonder if I'm losing too much current there?  I measured the current
> draw of the new horns, and it is about 5-6 amps each.  The old horn
> is about the same.  Even one of the new horns will not honk on the
> system.  It makes a little clink sound, but that's it.  Maybe they
> have a high "starting current?"  Looks like  from Bentley that the
> horn circuit is the only thing on a 20amp fuse, so I should be fine
> there.  I was thinking about using a relay but am open to any
> suggestions.
>
> Thanks,
> Edward