Main 12v feed for horn relay, where?

February 27

Hi all

ive decided to upgrade the rather weak stock horn (more like a whimper than a beep)

I have got a twin air horn to fit which requires a relay but part of the wiring diagram found is a direct live feed to connector pin 30 on the relay, my Battery (2.0 hybrid CHR) is in the boot! Is there an accessible 12v live feed in the engine bay I can spur off?
not looking forward to removing the front bumper either, seems a tad excessive to replace the stock pathetic horn, but can’t use the stock horn as too embarrassed and imho pointless as far to weak. Really could have benifited from a decent horn this morning when a white van pick up decided to pull off whilst I was passing beside him. Had to serve and luckily no on coming car. Van completely unaware that I was there. If I was on my Bike that’s fitted with twin airhorns he would have had to change his trousers as they are mega loud!!
any suggestions will be gratefully welcomed🙏

JonB

still love the car soooo much! 👏!

February 28

Why do you need a relay? I previously used a relay for headlights to shorten the feed to the headlights and the switch wiring to the relay.

An obvious live feed to the relay is off the fuse box but you don't gain by a relay.

February 28

17 hours ago, Woodie100 said:

I have got a twin air horn to fit which requires a relay

Is it a real air horn with a compressor? What's the current draw?

If they are just normal "snail" horns, chances are the OEM wiring will be fine and you don't need a new feed and relay.

17 hours ago, Woodie100 said:

Van completely unaware that I was there. If I was on my Bike that’s fitted with twin airhorns he would have had to change his trousers as they are mega loud!!

You are not alone 🙂 I know someone who has taken this whole horn thing to a new level and installed twin air horns from a railway locomotive. It's not just that it is LOUD, you feel it in your chest. Quite difficult to ignore.