Kawasaki GT750 some help please

[CherrytreeJed]

Hi, I've replaced the wiring loom, almost completely on my Kwak Trike, it's old school, but does have indicators, I have got most of the electrics working, except the front brake light and the horn.
I've followed the Haynes manual, which says that the horn button connects to the horn, the horn is connected to the front brake, which in turn is connected to the rear brake and onto the rear/brake light and a Fuse

My questions are

1) where does the horn get it's power from?
2) does each component need a separate earth?

Thanks in advance

[black-k1]

The "joke" answer is they all get their power from the battery! That said, it's also very true! I don't know what you mean by saying the horn is connected to the front brake which is then connected to the rear brake.

In simple terms each electrical component (horn, brake light etc.) will have a positive 12v feed and a negative earth feed. On most bikes, the frame is the earth so negative connections go either directly to the negative of the battery or to the frame.

Positive feeds will likely be switched either directly or through a relay, so the rear brake light is switched through the front brake and through the rear brake. The horn is switched through the horn button. Assuming no relays then those switches will need a positive feed which normally comes from a fuse. The feed from a single fuse can split across multiple switches and the feed to a fuse usually comes from a supply switched by the ignition, from the battery.

[CherrytreeJed]

Here's a very bad wiring diagram I have done, working from the Haynes and missing off all the stuff that isn't present, (such as side stand warning lamp, etc) following on from what you have said, then the positive feed comes from the 'flash' (Passing) button?
What's confusing is the rear brake does work, just not the front and the horn is dead too, thinking maybe a faulty horn?

[tvrolet]

Is the horn switch switching the earth? Can't remember what is was on, but something I rebuilt had power going direct to the horn (and brake lights too iirc) and the button connected it to earth. So these was no 'power' feed to the switch.

Edited...

Yea - just checked the wiring diagram for my old GPz and the horn and brake lights are switched negative, so the they are 'joined' inasmuch as they take the same power feed but have different spurs that switch them to earth.

Edited by tvrolet on Monday 26th November 22:46

[3200gt]

If its anything like my old z's then as said they all have common power with separate earths. The horn earths out through the switch touching the switch housing which in turn is touching the bars which in turn is clamped to the top yolk and thus to the frame.
So the question is, is the "live" wire connected to the horn live? and does it earth when the horn button is pressed.

[black-k1]

If the wiring diagram is correct your horn and brake light from the front brake are never going to work! It would appear that you are connecting –ve, through the horn switch, through the horn, through the front brake switch, through the brake light to … -ve!

If the blue wire connecting the horn and the front brake switch was made +ve (by connection to wire 3 as it appears to be the +ve feed to the various items on the bike) then it should work.

I would recommend investing the £10 or so in a digital multimeter and using it to confirm live wires, good earths etc.

[CherrytreeJed]

Thanks, that what I figured would be the case, will be sorting that next!

[CherrytreeJed]

Massive thanks all electrics working A OK! Now I've got to sort out the Starter Clutch, then she should start

With the wiring loom removed and for the most part binned!

[black-k1]

I'm glad it all works.