Air horn relay, do I need to use it?

Thanks for all the info, luckily they come with the correct relay and a wiring diagram.
I just need to find some time to fit it :)

And thankyou drivesafe for the diagrams, worked for me!

Steve, its a piece of cake, you'll need some spade connectors and a simple crimper, if you haven't already got 'em....

GQ

One tip,
Its probably in the instructions, but, make sure they are 45deg pointing downwards. I had some years ago and they filled up with water, mainly coz the angle was'nt enough and I think they picked up roadwash.
Still, we need it to rain for that to be a worry:(