Could do with a little bit of auto electrical help please.

[terravista]

Greetings
I know the basics of how lights work. Power goes through a switch to one terminal of the light and the other side is earthed. This may not be all lights, but seems to be pretty average.
So far so good.
I have an 10 year old Yamoto 250 Chinese quad bike that is fitted with a nuetral light and a reverse warning light on the dash, and neither of them work.
Both lights have a common black/white trace wire which I assume is the earth, and the other ones are separate colours.
When I stick a test light on the earth cables the test light lights up, and when I stick the test light on the other cable, the warning bulb lights up.
To my limited experience this does not seem to be correct and maybe something is wrong.
Does anyone have any hints besides dumping the Chinese crap quad and getting a Honda/Yamaha/ etc?
I can live without the lights but they'd be handy for expected relatively inexperienced riders planning on using it at Easter.
Thanks
Ian

[gronk]

You have got the test light lead going to negative ??

If you have, it seems like the wires you think going to negative are in fact positive ??...and you have an earthing problem ??


You know, I'm an elect fitter and I've never used a test light ( don't own one )

[Footy Shorts Shane]

Sounds like there's fault in the switch ( on the gearbox I assume? ) and it's not switching to ground.

Think of the way you described it, but backwards 

Power (common wire) to the lights, from the light to the switch (separate wires), through the switch to ground (gearbox), from the gearbox to chassis, then to the battery - terminal.

Without seeing it, I 'think' that's how it would work.

Shane.

[terravista]

You have got the test light lead going to negative ??

If you have, it seems like the wires you think going to negative are in fact positive ??...and you have an earthing problem ??


You know, I'm an elect fitter and I've never used a test light ( don't own one )

I had the clip end of the test lamp on the chassis, but I haven't looked to see if the quad is negative or positive earth.
A for not having a test light, I guess you have far mor effective means and tools than a supercheap $2 special.
Thanks
Ian

[terravista]

Sounds like there's fault in the switch ( on the gearbox I assume? ) and it's not switching to ground.

Think of the way you described it, but backwards 

Power (common wire) to the lights, from the light to the switch (separate wires), through the switch to ground (gearbox), from the gearbox to chassis, then to the battery - terminal.

Without seeing it, I 'think' that's how it would work.

Shane.

I understand the way you are thinking, but would have thought there was 2 switches, one for each action, and that would mean there was two faults. That may not be too unexpected with the country of origin.
Cheers
Ian

[Footy Shorts Shane]

There may be two switches.
My guess would be to look for a 3 pin switch near the selector shaft.

As I said though, only guessing. 

Shane.

[feisty]

Sounds like the light is using a switched earth.   i.e. constant 12v to the light and the switch actually switches the earth.  Basically the same way car horns are wired.  Constant 12v to the horn and the switch earths it.   This is the same for+ or- earth vehicles.  Could be wrong though. ... switched earths always used to catch me out

[terravista]

Sounds like the light is using a switched earth.   i.e. constant 12v to the light and the switch actually switches the earth.  Basically the same way car horns are wired.  Constant 12v to the horn and the switch earths it.   This is the same for+ or- earth vehicles.  Could be wrong though. ... switched earths always used to catch me out

That sort of makes sense. It could explain why the test lamp works on one wire, and the warning light works on the other......I think.

[AdrianLR]

This looks to be the wiring diagram:



Switched earth.

[prodigyrf]

Yep that's the way Jap bikes work with live (universally positive) to the warning light and then to the switch that earths it (universally negative)at the appropriate trigger point ie in the case of a neutral light there is a contactor on the gear selector drum that makes contact to earth when it's in the neutral selection position (or reverse too in the quad case). Ipso facto you must have live feed to the globe (central contact) and the exit wire from metal body of the globe will still be positive all the way to the gearbox switch. So where it enters the gearbox earthing it out should activate the light (or test positive) for a good light and wiring. Then it's down to the switch and you could test that with an ohmmeter or powered tester from the wiring connector into the gearbox and earth (it will have a connector to allow for easy engine/gearbox removal). If that doesn't show a connection (light or nearly zero ohms) then if the switch is not external, you've got yourself a gearbox teardown to fix the problem internally and is it really worth that?

[prodigyrf]

Ok from your wiring diagram both lights 5 reverse and 6 neutral have brown positive feeds and the reverse light to gearbox switch is green and brown while the neutral is sky blue so check them as described before.

Edit: Woops cross posting and assuming that's your actual wiring diagram but if not it should be something similar.

[terravista]

Thanks prodigyrf. The wiring diagram looks close enough to fiddle around with. By the results I am getting it pretty much makes the switch the culprit. And no, pulling the gearbox apart is not worth the effort of what is a minor item.
Thanks
Ian

[Footy Shorts Shane]

I would think the switch would screw in from the outside of the box?

[HKB Electronics]

I'd agree with that, you wouldn't think they would mount the switch inside the gear box
due to oil and lack of access.

[terravista]

I would think the switch would screw in from the outside of the box?

I hope you are right. I had a BMW K100 bike up until last year and was told the nuetral light switch was inside the gearbox and the estimate to replace it or clean the contacts was over $600.
I had a quick look around the gearbox for connections or switches and found none, I might have to get down and dirty and have a better look on the weekend.
Thanks

[prodigyrf]

I would think the switch would screw in from the outside of the box?

Not always but yes I'd definitely look for a screw in contact switch/es on the gearbox somewhere (might look something like a temp sensor but actually be a spring loaded earthing contactor for the selector drum)

Here's some pics bearing in mind some cap the end of the selector drum but some are electronic hall sensors nowadays-
http://www.bing.com/images/search?q=neutral+switch+motorcycle+gearbox&qpvt=neutral+switch+motorcycle+gearbox&FORM=IGRE

[prodigyrf]

More like gear position sensors for dummies nowadays-
http://motorelectricalignition.com/products/neutral-switch-gear-position

[terravista]

Had a good look around with a torch and mirror, under and over the whold gearbox area and can't find anything that looks like a terminal or contact or even wires. Bloody Chinese, probably put the warning lights on just for show.
I guess the users are just gonna have to do it the old tech way.
My Francis Barnett Falcon doesn't have a nuetral light and no reverse so the quad will be good practice for them.
Thanks for the help though.......shoulda gone Japanese, but then all I could have afforded would be the warning light bulbs.
Cheers
Ian

[prodigyrf]

Just bear in mind the neutral and reverse wires could be bundled up with the CDI wiring harness and once under the engine/gearbox sidecovers hive off to their appropriate switches/contactors but I'll take your point about China Inc here although it may be they have different models for on/off road for different markets and yours is strictly off road so although the instrument lights are there, they were never wired up from the factory.

Edit: Thinking about that, for the reverse/neutral switching to work you'd expect the quad to be fitted with a minimal battery and charging system for them to work as well as a horn, brake light and indicators (bearing in mind lights can run direct off AC alternator in these off roaders) so no battery may mean none of these peripherals are fitted for rego purposes.

[terravista]

Edit: Thinking about that, for the reverse/neutral switching to work you'd expect the quad to be fitted with a minimal battery and charging system for them to work as well as a horn, brake light and indicators (bearing in mind lights can run direct off AC alternator in these off roaders) so no battery may mean none of these peripherals are fitted for rego purposes.

Yep, it has a battery, headlight high and low beam, tail and brake lights, but no indicators. The warning lights have bulbs and wires running down a pastic tube but no visible exit.
I can deal with it, for what I paid it is only a small inconvenience.
Cheers
Ian

[prodigyrf]

Chuckle... thinking of the days when they could draw the complete wiring diagram on the mobike, in this case a 1968 DT1 250cc Yamaha-
http://www.bing.com/images/search?q=dt1+yamaha+wiring+diagram&FORM=IQFRBA&id=934445806B49A5B087D60CF19BAF44FD9F847DE2&selectedIndex=0#view=detail&id=934445806B49A5B087D60CF19BAF44FD9F847DE2&selectedIndex=0
The bike that launched a generation off road biking and dirt racing and if you were game swing your leg over the 360cc  big brother but never let the kickstarter leave your boot or wimp out kicking the mongrel