Horn Relay

[the_lone_wolf]

Originally Posted by Baph

That's the reason that Ford use diodes.

how would a diode help?

if you have a cable suitable for 15A, say from the headlamp circuit, and you ground a 30/40A circuit through it you'll damage the cable shirley?

Originally Posted by the_lone_wolf

how would a diode help?

if you have a cable suitable for 15A, say from the headlamp circuit, and you ground a 30/40A circuit through it you'll damage the cable shirley?

So long as the ground cable used is capable of the max current, the rest is unaffected because of the diode.

In your example, the "sub standard" wiring would be in the headlamp circuit, but the 30/40A wouldn't be able to go through that circuit due to the diode. So long as the ground cable can take 30/40A, it's all good.

I can see your thinking, but if you change the path to ground from the headlight through your new circuit instead, the problem goes away.

[the_lone_wolf]

Originally Posted by Baph

I can see your thinking, but if you change the path to ground from the headlight through your new circuit instead, the problem goes away.

thought that's what you were on about


when it comes to the bike i'd rather leave the stock wiring alone and run new circuitry from it, like i did for the HID conversion:

Originally Posted by the_lone_wolf

when it comes to the bike i'd rather leave the stock wiring alone and run new circuitry from it

You've not seen my bikes wiring have you? Clicky (to avoid scaring folks it changes quite often back there).

[yorkie_chris]

Whoa, mine isn't the worst in the world! (should see the tangle behind the headstock on mine though...)

[the_lone_wolf]

Originally Posted by Baph

You've not seen my bikes wiring have you? Clicky (to avoid scaring folks it changes quite often back there).

Decided to fit the horn today... remember on the relay...

30 - to horn.
87 - to live feed.
85/86 - to original horn contacts.

Lovely jubly, 136 DB horn. Jax heard it and said 'holy f**k'.

The Stebel's don't earth off the mounting contact so I had to run a earth feed back to them too.

Had some problems with the horn original feed wires as water had got into them and corroded the wire, so had to strip the back down to half there length. So when I did manage to get the horn going it did jump a little as it was on my lap.
Now I just need to figure out why my rear lights have stopped working.

136dB? You lightweight!

[DarrenSV650S]

Ok can someone please confirm how the connections go.
On my relay I have 30, 85, 86, 87 and 87a

Originally Posted by DarrenSV650S

Ok can someone please confirm how the connections go.
On my relay I have 30, 85, 86, 87 and 87a

Funny you should ask, I sent the following PM just a few minutes ago to someone else...

Originally Posted by me

Maybe it's better for you to think logically about the electron flow through the entire circuit.

You want the existing horn wiring to activate the relay. That means taking the connector from the stock meeper, chopping it in half, and plugging it into the coil on the relay (pins 85 & 86 - doesn't matter which way around).

Now turn the ignition on, hold the relay, and hit the horn button. The relay will click to confirm that you're OK so far, but it's easier to feel than it is to hear it.

Next, you want to power the new horn, using the relay as a switch (due to the higher power draw of the new horn you don't use the existing wiring as it'd melt!).

So, first things first, power from battery positive. That goes to 87 on the relay. This is the "Normally Open" pin, which means that normally, the circuit isn't complete to this pin, unless the relay is "on" (when you hit the horn button).

Next, from pin 30 (common pin shared between 87 and 87a) to the horn, again, it doesn't matter where on the horn, there's no diodes to worry about.

Then the last step to complete the circuit, from the remaining connection on the horn to ground (frame/battery negative). My advice here is to use one of the horizonal bolts that hold the bikini fairing to the bike.

As I already mentionned, which way around you hook up 85 & 86 really doesn't matter. The same is true of 87 & 30. You can wire from the battery positive to 30, and from 87 to the horn if you like. I just use 87 as the power feed because it's habit, and 30 is always refered to as the "common" which I interpret as "ground" - some people define it the other way around, saying the 87/87a pins should go to the device to be powered.

If all else fails, have a look at this link to remind yourself of the inner workings of the relay. http://www.classictruckshop.com/club...osch/relay.htm

Lastly, print this PM & have it handy while you're doing the wiring.

HTH.

Change "PM" for "post" on that last sentence.