2004 FZ6 Will Not Start With Headlight Fuse Connected

[Anthrax1039]

Headlights weren't working, finally got around to checking the problem: fuse had blown.

The bike has obviously been down a road at some time as there are Twin Dominator headlights fitted to it. So nothing lighting wise is particularly stock. For full disclosure, had an issue with water in the tank a few weeks back, headlights had worked up until this time. I believe this to be unrelated but if I knew what I was doing I wouldn't be asking!

I replaced the fuse, attempted to start the bike and got nothing. The engine kicks and then fails to start. I removed the fuse, starts.

Fuse in again, removed bulbs, failed to start.

I have also had a look through the Owners Manual and tried the diagnostic tools within the bike. All sensors, switches and voltages register as normal.

Would anyone here happen to have an idea why when the fuse is in for the Headlights (and seemingly only the headlights) the bike fails to start?

Thanks in advance,

Anthrax
____________________
'59 CBF125 (Written off) - '08 Varadero 125 (Sold) - '00 GPZ500s (Sold) - 1990 ZX4R (Sold) - '53 FZ6 (Sold) - '64 V-Strom 650 - '02 FJR1300
Cage Jan 2011 - CBT Sept 2011 - Theory Feb 2012 - Mod 1 Feb 2012 - Mod 2 May 2012

[Taught2BCauti...]

It could be your battery on it's last legs.

Put a voltmeter across it and note the readings with and without the headlamps on.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[Anthrax1039]

I won't be able to get a reading with the headlamps on sadly, they will not come on unless the engine is running on this bike.

I'll run the multi-meter across the battery tomorrow, didn't think to check as without the fuse it started first time on the button with no issues.
____________________
'59 CBF125 (Written off) - '08 Varadero 125 (Sold) - '00 GPZ500s (Sold) - 1990 ZX4R (Sold) - '53 FZ6 (Sold) - '64 V-Strom 650 - '02 FJR1300
Cage Jan 2011 - CBT Sept 2011 - Theory Feb 2012 - Mod 1 Feb 2012 - Mod 2 May 2012

[Taught2BCauti...]

[Anthrax1039]

I don't recall them coming on in the past either, but you could be right.

If I recall my voltage was at 11.6 earlier when dicking about on diagnostics. I had to double check with my mate who had been up at the time.

I'll stick the charger on it in the morning, if it lives, you are right and I've found the problem. I'll also have another problem: a hole in my pocket for a new battery.

Thanks for the help!
____________________
'59 CBF125 (Written off) - '08 Varadero 125 (Sold) - '00 GPZ500s (Sold) - 1990 ZX4R (Sold) - '53 FZ6 (Sold) - '64 V-Strom 650 - '02 FJR1300
Cage Jan 2011 - CBT Sept 2011 - Theory Feb 2012 - Mod 1 Feb 2012 - Mod 2 May 2012

[Anthrax1039]

Update:

Checked my battery voltage earlier and was at 12.4. In the interest of belt and braces I whacked the charger on it for a few hours. Charger eventually entered maintain mode at 13.2 Volts.

Battery when engine running at idle - around 13.2 volts give or take.
When revved to around 4k - 14 volts. As normal really then.

Once the engine is switched off, we are sitting at 12.6.

Still cannot get it to start with that fuse in.
____________________
'59 CBF125 (Written off) - '08 Varadero 125 (Sold) - '00 GPZ500s (Sold) - 1990 ZX4R (Sold) - '53 FZ6 (Sold) - '64 V-Strom 650 - '02 FJR1300
Cage Jan 2011 - CBT Sept 2011 - Theory Feb 2012 - Mod 1 Feb 2012 - Mod 2 May 2012

[HKJohn]

[Taught2BCauti...]

I have had a look at the wiring diagram, and there are a couple of things that stand out.

1. The Headlamp Dimmer Relay coil (60) is fed from Fuse 46, and triggered by a Yellow/Black wire that comes from the ECU (20). Fuse 46 doesn't supply power to anywhere else, other than the live side of the Dimmer Relay contacts.

2. The Fuel Injectors (21-24) and the Ignition Coils (27,28) are also triggered from the ECU (20).

3. The Dimmer Relay (60) doesn't actually make any sense - I think it is more of a 'Headlamp Enable' relay, because it needs to be actuated for either the main or dip beam to work, and that is controlled by Switch 53, and since it is the ECU that actuates it, it must be there to allow the engine to start with the headlamps off, and then 'enable' them once the engine is running.

Presumably, Fuse 46 is the one that affects your starting issue - but do you know whether it is the Ignition Coils or the Fuel Injectors (or both) that are affected when Fuse 46 is present and you try to start the engine?

Does it make a difference to the starting if the Headlamps are on Main or Dip?

What happens if Fuse 46 is in and the headlamp bulbs are disconnected?

Will the engine start if Fuse 46 is present and you remove the Dimmer Relay?

With the Dimmer Relay removed, can you use a volt-meter to see what is happening on the Yellow/Black wire at the Dimmer Relay socket? (I would expect to see it 'floating' with the engine stopped, and going to 0V when the engine is running).

Can you trace the Yellow/Black wire from the Dimmer Relay (60) all the way back to the ECU (20) and be certain that it isn't damaged or shorting to earth?

That should narrow it down between a wiring fault, a blown Dimmer Relay, or a dodgy ECU.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[chris-red]

What about putting the fuse in while the bike is running?
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[Anthrax1039]

[Anthrax1039]

[Taught2BCauti...]

As you have already eliminated the bulbs and the Dip Switch, the next thing to try would be to leave Fuse 46 in, and pull the Dimmer Relay.

If either the Dimmer Relay's internal diode or coil have failed short circuit, it could be sending 12v to the ECU via the Yellow/Black wire, and this could stop the engine firing (if the ECU sees this as a fault condition).

This is how I think it should work:

When the ignition is on and the engine is not running, the Yellow/Black wire is floating - i.e. neither earth or live. You can check this with a voltmeter.

When the engine is running, the ECU connects the Yellow/Black wire to earth, and this activates the 'Dimmer' Relay, causing the contacts to close, which then turns on the headlamps, with main or dip depending on the position of the dip switch.

If the engine fires with Fuse 46 in and the Dimmer Relay removed, then you need to test the relay, and replace it with the corret type if it is duff.

If you still have the problem with a good relay, then I would suspect the ECU.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[chris-red]

[Anthrax1039]

[Taught2BCauti...]

I think we are definitely getting closer to a solution

So far, we know it's not the fuse or the relay, but it does have something to do with the Yellow/Black wire and the ECU.

The next thing I would look at, is what sort of signal appears on the Yellow/Black wire, first when the Dimmer Relay is in and the engine won't start, and again, when the relay is out and the engine does start.

For both tests, connect one side of your voltmeter to the Yellow/Black wire, and check the other side of the voltmeter against live and earth on the battery, with the batter on.

Then, with the relay out, check the same again with the engine stopped, and the engine running.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[Anthrax1039]

I'll look to try and get this done on Tuesday. Unfortunately away this weekend.

Thanks again,

Anthrax
____________________
'59 CBF125 (Written off) - '08 Varadero 125 (Sold) - '00 GPZ500s (Sold) - 1990 ZX4R (Sold) - '53 FZ6 (Sold) - '64 V-Strom 650 - '02 FJR1300
Cage Jan 2011 - CBT Sept 2011 - Theory Feb 2012 - Mod 1 Feb 2012 - Mod 2 May 2012

[Anthrax1039]

Relay out:

Test against Earth:
Ignition on: 0.01
Start: 0.26 jumps to -0.22

Test against Live:

Ignition on: 12.45
Start: 13.76


Relay in:

Test against earth:

Ignition on: 12.45
Start (attempt) 9.9

Test against Live:
Ignition on: 0.04
Start (attempt) 0.0/-0.0


I think that's all the figures you were looking for.

Thanks,

Marc
____________________
'59 CBF125 (Written off) - '08 Varadero 125 (Sold) - '00 GPZ500s (Sold) - 1990 ZX4R (Sold) - '53 FZ6 (Sold) - '64 V-Strom 650 - '02 FJR1300
Cage Jan 2011 - CBT Sept 2011 - Theory Feb 2012 - Mod 1 Feb 2012 - Mod 2 May 2012

[Val]

Would you test the dimmer relay again:

https://www.manualslib.com/manual/854621/Yamaha-Fz6-N-2004.html?page=61

https://i59.tinypic.com/2ed8cis.jpg

[Taught2BCauti...]

With the readings you are getting when the relay is out, I would expect the lights to be on when the ignition is on, regardless of whether the engine is running or not, but the Yellow/Black wire shouldn't provide an earth until the engine is running.

Just to clarify:
Relay out:

Test against Live: (Red meter lead to battery +, Black lead to Yellow/Black wire)

Ignition on: 12.45
Start: 13.76

-

The only thing left that I don't think you've already tried, is to start the bike with the relay out, then replace it once the engine is running at fast idle.

If that causes the engine to die, I would suspect the ECU, if not I would suspect the battery.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[Anthrax1039]

[0l0dom0l0]

I can't help with a solution, but if it makes any difference the headlight comes on when the engine is started on my FZ6 not when the ignition is turned on.
____________________
CBT Passed: 30/08/2009, Theory Passed: 31/08/2010, Mod 1 Passed: 6/9/2010, Mod 2 Passed: 13/09/2010. Restriction ended 13/09/2012.

Bikes: 2007 Derbi GPR 50, 1998 Yamaha Fazer 600 (written off), 2002 Yamaha Fazer 600, 1994 CBR 600F, 2003 Triumph Daytona 600, Kawasaki ZX6R J1.....Current: 2006 Yamaha FZ6, 1998 Suzuki TL1000R and a Honda VFR 400 NC30.

[unitynotsocri...]

Shot in the dark............check the Genny coil that feeds the lighting circuit?
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[Anthrax1039]

Whilst I appreciate this is a very, very, old post now: here is the resolution!

I decided to start tracing wires again working back from the fuse box after bursting out the loom. I found multiple connectors all showing signs of corrosion and on the closest original cable to the lighting relay I found the cabling to have gone black.

Cables trimmed, new connectors added, tested everything and the bike now starts and runs as it should with the fuse in and with the lights connected.

Updated in the off chance anyone else ever has a similar issue.
____________________
'59 CBF125 (Written off) - '08 Varadero 125 (Sold) - '00 GPZ500s (Sold) - 1990 ZX4R (Sold) - '53 FZ6 (Sold) - '64 V-Strom 650 - '02 FJR1300
Cage Jan 2011 - CBT Sept 2011 - Theory Feb 2012 - Mod 1 Feb 2012 - Mod 2 May 2012

[chris-red]

OP Delivered!
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[blurredman]

But: 5 years later and almost to the day?

Did you just fix it- or did you fix it 5 years ago?
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1973 MZ ES250/2 - 17k. , 1979 Suzuki TS185ER - 9k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 38k, 1989 MZ ETZ251 - 49k