Damsel In Distress - Daytona 600 Horn & Brake Light

Hello All

I've been a bit of a lurker on here since I first bought my Daytona 600 (2004) a couple of years ago.
Up until now we've managed to just about work out the various faults that seem to crop up (on a far too regular occurrence) but this one has truly stumped me and I'd GLADLY receive any help you can offer.

(Apologies in advance if this has already been asked somewhere else...)

The horn does not work and nor will the brake light (but only when trying to use the front lever, ie the foot peddle still turns on the light.) FYI the indicators still work - I only note because the threads that I have seen all note that their similar problem also includes this issue.

So far I've tried:
- all the fuses,
- all the relays,
- checked the switch,
- bulbs,
- wire from the switch to under the air box has continuity

None of these seem to have faults.

Consider me well and truly stumped...

Please and thank you in advance.

B

 

Welcome Bekah
I’d say your front brake light problem is possibly a faulty microswitch at the lever. Can you hear it click when you pull the lever?
As for your horn, it could just have given up the ghost, or could be the switch, or even a wiring fault.
How handy are you with tools? Do you have a multimeter? Do you have a workshop manual/Haynes?
Let us know and we’ll try an help you out.
Post a pic of your bike too, we like piccies.

 

Its not the switch as I have taken it off, continuity through it when switch depressed and not when not (or other way round, cant remember now), So the switch seems fine.

Have started going through the wires and all so far have continuity but dont have a multimeter, so i cant be sure they are getting full voltage through them (if it was shorting on the frame etc) although that seems unlikely as all the fuses are still fine..... Have a workshop manual but not been able to use it to find the fault.. Yes pretty handy with the tools!

 

Bekah obviously I dont know how handy you are but here goes....

Get a piece of wire and fasten one end to the positive of your battery, be careful with the other end, twist and stick the copper strands will do. Touch the positive side of the horn wire connector, does it make a sound?
Horn proven one way or the other.

Obviously your brake light works but is it just simply the switch?
Same again touch the wire from the switch to the bulb and does it light?
If so its the switch. If not then ummm!

Obviously the hard part with two wires is deciding which one but a momentary touch (direct short) shouldn't be a major issue. Indication of this will be immediate sparks when you touch the wrong one

A multimeter could refine these suggestions but it depends how equipped and knowledgeable you are with such tools.

 

Get yourself a multimeter Bekah, it’ll pay for itself in no time.
They’re cheap as chips these days for a basic one, or even one with lots of functions like @Duckadiledundee got recently from Amazon.
It’ll make fault finding much easier if you can confirm voltage at the right points in the loom.

 

Hello and welcome to the forum Bekah.

 

One of these could be very useful for you too.
https://www.toolport.co.uk/automoti...uits-continuity-polarity--voltage-31772-p.asp
A bit safer than just probing around with a live bit of wire.

 

Hi Bekah

 

Live life on the edge eh @freck

 

Bekah Scott.
Yes take the wires of your brake switch and short them against each other if the brake light works it's your switch. Same as your horn just get a battery and test to see if it works. If not i would get back on here and eventually we will work it out. When you checked those fuses did you try something like a bulb between the live and earth or meter as they can fool you some times did me. By the way welcome to the family. And yes do show us your steed just hit the upload a file button bottom right corner and keep all the inmates happy with a picture. And it's great to see another Lady join the Family.
Regards And Luck
Joe.

 

Hi Bekah and welcome

 

Hi and welcome.....

 

Hi Bekah and Welcome to the Forum, electrics really aren't my thing but it looks like @freck & @Eldon have you covered, don't forget to let us know how it pans out.

 

Welcome to the forum

 

You wanna be careful there Bekah that'll get you into trouble,
On a serious note the advice given should see you right
Oh and welcome to the forum

 

Welcome from a fellow newbie

 

General current flow:
Battery -> Fuse 4 -> Key-Switch -> Common Node for Brake light, turn signals and horn
There are actually two different colour circuits leaving the Key-Switch (on main harness side of connector)
Orange/Green feeds front brake switch and turn signals; black/blue feeds horn and rear brake switch - even though these are different colours, they are all at the same node/source.
When you first hear that brake light and horn does not work, you normally question whether the turns work (and you affirmed that they do) and generally the failure would be either fuse 4 or the key-switch. The spoiler here is that one of the brake switches works and so do the turns, so the node must be supplying power through at least the fuse and the key-switch (and you might expect the other two elements attached to the node, that do not wok, to be also good on the positive power side, since all are connected together)

Regarding this:

Well, respectfully, no - the horn positive is constant with ignition on (from node mentioned above); it is not what is controlled by the horn switch, the ground side of horn is what is switched; so connecting positive power to the horn plus will NOT make it sound, you would additionally have to actually press the horn button to complete the circuit (but if doesn't sound even with horn button pressed, still does say whether is horn or the negative wiring via switch to ground)

Bekah - do you have access to a meter? If not, as suggested consider buying a cheap one - really need it to make much headway

Here's the best way to use it - set it to DC Volts and put the black probe on your battery negative and leave it there, only moving the red probe to different points.
Now take the red probe - the first place to test is Fuse 4 - you do not remove the fuse, touch the probe tip to the the exposed metal tabs on the top of the fuse on each side; you should get 12V on both sides;



You would expect that to be good, since you already confirmed the one brake light and turns working

Next - we need the key-switch turned on for all the following tests - reconfirm that the rear brake switch indeed operates the brake lamp and that the turn signals work - affirm on both?

So assuming the rear brake and the Turn Signals DO work, that will confirm that the key-switch is actually transferring power correctly at least through that section of the circuit.

Next - we mentioned that the Horn and Front brake switch are also connected to that same node; so go to the horn itself (not the switch) and now measure voltage on the Black/Blue wire (on the positive terminal) - that SHOULD also be 12V - if it is NOT is suggests there is a break somewhere in that node between the Horn Black/Blue and the Key-switch output - that would be a crimp somewhere in the harness. Now - since the front brake is on orange/green and the horn on Black/Blue it would be odd - but not impossible - that both of those positive supplies are disconnected by virtue of a bad crimp - however you must check, just for the purpose of progressing with the diagnosis.
And similarly for the Front brake switch - carefully pull the two terminals off the brake switch on underside of the master cylinder - check again individually on each of these two wires with your red probe - ONE of them should be +12V, the other not.
Again, if you do not have 12V on ONE of those wires, then you have a break somewhere on the main harness (or in the case of the brake perhaps a broken wire or badly oxidized connection at the main bar switch connector)
Please report back if you find the case that you do NOT have 12V on the Black/Blue at the horn AND/OR ONE of the two wires that go to the front switch

So let's assume that (hopefully) you DO have 12V at those two locations (the horn and front brake):
The next step now is going to be different for each device
First the Brake - while you have the two terminals disconnected from the switch, touch them together (be sure you get a good physical metal to metal connection) - the brake light SHOULD come on. (again, the key must be on) if it does not, again I would look to the main connector for that right bar switch (I can give you specific pin numbers/wire colours to check)
If it does NOT please check back and I will give further guidance
If light DOES come on, then it means it is the switch (or actuation of the switch by lever) that is problem
The horn - assuming you have affirmed you have 12V at the Black/Blue wire, you now want to 'ground' the other terminal - take a piece of wire and touch one end to the horn negative terminal (the one with the Purple/Black wire) and a good ground point on the engine (a stud or bolt) - the horn should sound. If it does not, then your horn must be bad (i.e. you have validated it has 12V on one terminal, grounded the other - if it does not sound, horn is bad)
If Horn DOES sound, that means the ground circuit through the horn switch is the problem; now there is a fairly common issue on most of the Triumphs of that generation - there is a crimp on the ground wire that supplies the horn button on the left switch assembly harness - this crimp is maybe 9-12" down the harness from the bar switch - the crimp fails and the wire breaks and you get no connection with the actual switch.

Hopefully that should give you something to go on
Please report back with deviations to the expectations I said you should have at each of those test and the data accordingly
Good Luck!

 

Here's simplified circuit for you

 

Hi Bekah and welcome to the forum best of luck sorting the issues, you sound very handy

 

@D'Ecosse nice in depth explanation and I hadn't expected it to be switched negative so thanks for informing me that it is.
Very helpful to one and all