Horn relay...is it needed?

Liverpool-Lad · 16 Jan 2010 at 18:22

My Capri already has 2 seperate horns (high & low tone) but to be fair, theyre pretty pants!

Now, Ive ordered some better Stebel Magnum horns and they come with a relay...is it necessary to wire this in or simply replace as the wiring is already there?

Cheers.

agw_01 · 16 Jan 2010 at 18:28

Depends what the original wiring is rated for.

If the Magnum is anything like my Nautilus I'd use the relay and uprated wiring. Some of those horns can draw quite significant power.

PhillyDee · 16 Jan 2010 at 18:57

I have the stebel magnum horns myself. Replaced a single horn for a 2 tone.

The Horns draw more than 10A (Normal fuse for the horns) and the wiring in your car is probably only rated for the 10A fuse.

They recommend a 20A fuse for the magnums.

Liverpool-Lad · 16 Jan 2010 at 19:01

How do they sound? (Not heard them apart from a sound clip)

Flukester · 16 Jan 2010 at 19:16

it's not really what your wiring is rated at (likely to be ok), it's the actual switch for the horn.

without a relay a normal switch just can't handle large currents...

i have a nautilus on bike and it's pretty loud, relay came with it

PhillyDee · 16 Jan 2010 at 19:27

Liverpool-Lad said:
How do they sound? (Not heard them apart from a sound clip)

Great!

Much better and certainly much louder!
I have a Rover Streetwise and Rover started skimping on certain things. The Horn was one of them. Instead of the normal twin tone, they only had one and it sounded rather gay.
I tried the magnum out on a battery pack and it really is deafening. Of course, when it is mounted inside the engine compartment (Or just behind the bumper on mine) facing down it is quieter. Still louder than most cars, and always fun when someone is about to get in the car . . . . . .

And good point about the switch!

Fantom · 16 Jan 2010 at 20:41

I have a Nautilus and have just wired it up where the original horn is, would you think that it would be louder if I used chunky wire and wired a relay in?

*Moangroan* · 16 Jan 2010 at 20:48

without a relay both the switch and wiring need to be rated slightly above that of the current to be used.

I would stick to the relay mate.

Just have a look on google for automotive relay wiring if you're not sure how to wire up and dont forget the fuse. The whole point of a relay is to be able to use low current wire and low current switches to operated devices...fog/lights that use higher currents.

Flukester · 17 Jan 2010 at 08:23

Fantom said:
I have a Nautilus and have just wired it up where the original horn is, would you think that it would be louder if I used chunky wire and wired a relay in?

It probably won't be louder, as I suspect the wiring would handle quick bursts of current, but a relay will probably save possible meltdown of your horn switch and possible heating issues with low rated wire (if used) ....heating is a bad bad thing when overcurrent occurs....you could set fire to your car.

You could do with measuring the current your old stock horn drew... then the nautilus, if they are similar then no worries, if the nautilus is double then it's time to fit that relay