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Change horn wiring from steering boss

tims31 - 9/5/17 at 04:50 PM

Can someone look at the below wiring diagram and tell me if I have the right idea please.

The current config has the wiring going through the steering boss as per the top diagram but post IVA I want to remove the Sierra steering wheel and fit a smaller wheel and have just a small push button for the horn. Having heard that the current for the horn can be about 10amps and that it may burn out the switch I want to wrie through a relay as per the lower diagram. I will probably wire it this way now and just use the steering boss to activate the relay to save taking the dash apart again.

Two questions please,
Is the lower diagram correct

Is the lower diagram correct?
Can I take the 12V feed from pin 30 through the switch and on the relay?

Description

gremlin1234 - 9/5/17 at 06:05 PM

looks fine.
I would take the power to the relay itself, from the same fuse supplying the horn

dit
but why not something like this. (I know its the american site, but just to show the concept
https://www.amazon.com/Universal-Golf-Tractor-Switch-Button/dp/B008A7LNMO

edit 2
or
http://www.carbuildersolutions.com/uk/all-black-push-button-horn-switch
but you do say you want the button on the steering wheel, so a relay is the way to go ;-)

[Edited on 9/5/17 by gremlin1234]

907 - 9/5/17 at 07:36 PM

My Momo is a small wheel and has a small horn push in the middle, and passed IVA with no mods.

tims31 - 9/5/17 at 08:03 PM

quote:
Originally posted by 907
My Momo is a small wheel and has a small horn push in the middle, and passed IVA with no mods.

Thanks but I already have the Ford steering boss and wheel I just want to be able to wire a horn button onto it once I replace the Sierra one post IVA

Steering-boss

[Edited on 9/5/17 by tims31]

ste - 9/5/17 at 10:00 PM

you're better off switching the earth and not a live wire.

rodgling - 9/5/17 at 10:03 PM

quote:
Originally posted by ste
you're better off switching the earth and not a live wire.

Why?

myke pocock - 10/5/17 at 09:14 AM

Probably going to dig an enormous hole for myself as I dont understand the ways of the electrickery but why not simply use a switch that will take the proposed current or can you not get a switch that matches what you want in looks? Save all the fannying around with relays.

tims31 - 10/5/17 at 09:17 AM

quote:
Originally posted by myke pocock
Probably going to dig an enormous hole for myself as I dont understand the ways of the electrickery but why not simply use a switch that will take the proposed current or can you not get a switch that matches what you want in looks? Save all the fannying around with relays.

These buttons/switches tend to be quite big to carry the current and also protrude quite a way back too with ugly screw terminals at the rear. Just I would prefer to use small buttons and keep it quite neat.

Description

Quite easy to use a relay really, just wanted to check my circuit was ok?

[Edited on 10/5/17 by tims31]

[Edited on 10/5/17 by tims31]

mackei23b - 10/5/17 at 10:17 AM

It's not just the current, horns are generally are inductive, hence the relay to handle this.

Cheers

Ian

quote:
Originally posted by rodgling

quote:
Originally posted by ste
you're better off switching the earth and not a live wire.

Why?

tims31 - 10/5/17 at 03:48 PM

quote:
Originally posted by ste
you're better off switching the earth and not a live wire.

Well its all wired up and working, decided to go switched earth as suggested.