S4 Lighting relay where is it ???

[LVC]

Bonjour all - long time no speak (2017 my last login ..... shame on me)...

Anyway the S4 is still alive and kicking up dust on the French roads near Le Mans ....

I need your help ..... headlights/rear lights don't work ...

Parking light front and rear does, passing beam/flash does but dipped and side lights and rear lights don't.

Fuses are good (unless some bugger has hidden a special one somewhere I haven't found) so am thinking "relay" which is a micro-switch .... so before I take the handlebar switch apart can anyone please tell me where the chuffing relay is for the lights on a 2001 S4..... There's three obvious ones by the air filter and swapping them around hasn't changed anything so I'l guessing it's somewhere else ????

Thanks in advance :mand:

Photo of the beast for those that remember me ^^

https://i95.servimg.com/u/f95/12/39/65/39/duc0110.jpg

[Darren69]

Iirc there isnt a lighting relay so your problem may well be a faulty switch.

[LVC]

Iirc there isnt a lighting relay so your problem may well be a faulty switch.

Thanks.

I've just taken and rebuilt the switch (need about 10 hands with 20 fingers on each) to get it all back in and all good .... there's no "positive" getting to the lighting part of the switch so currently into the Workshop manual trying to figure out where it gets its power from.

Yes no relay on this model from what I can see (the ST4 has though annoyingly).

Will keep looking :banghead:

[Flip]

Sounds right if it switches the ground.

So when you say ‘parking lights’ work do you mean when the key is turned to ‘park’ after the steering lock position?

Do you get the position/side light on with a tail light with light switch in the on position with the ignition on?

Ok so no dip beam but does the head light come on with the ignition on and switch set to high beam (not the pass/flasher) or is it the complete head/tail light circuit out?

[LVC]

Sounds right if it switches the ground.

So when you say ‘parking lights’ work do you mean when the key is turned to ‘park’ after the steering lock position?

Do you get the position/side light on with a tail light with light switch in the on position with the ignition on?

Ok so no dip beam but does the head light come on with the ignition on and switch set to high beam (not the pass/flasher) or is it the complete head/tail light circuit out?

Hiya, Yes turn the key beyound steering lock to park and the front and rear "sidelights" come on as does the dash.

I get nothing at all, neither front nor rear, side lights or dipped beam when the switch is activated and ignition is on. So complete head/tail light circuit is indeed out.

High beam only works as the pass/flash and blue main beam comes on on the dash cluster.

Brake lights front and rear work also so does indicators and in fact everything else just no lights :(

[Flip]

Okay apologies for this question - we can pin this one down but do you have a multimeter?

My feeling is the handlebar switch is giving the issue as you have nothing working from it. You have side and tail light from the park position- which circuit is switched by the the ignition barrel.

So you need a meter to check if there is continuity from the switch to the corresponding pins in the connector from it.

On my 900 they are in a ‘superseal’ connector fixed to the headlight bracket but I am not so familiar with an S4 to know exactly where to find it I’m afraid, so you may have to play ‘follow the wires’ from the switch until you track it down.

[Dukedesmo]

Obviously if the switch is faulty you will need to repair/replace if first but if you then modify the wiring to add a relay (switching through heavier duty wiring), you will get a brighter and quicker-on headlight whilst reducing the chances of overloading the switch again.

[LVC]

Yes indeed - will go check the switch wiring (all looked good when I had it apart) and report back :biggrin:

[LVC]

Checking complete - switch is functioning correctly (checked side/dipped light switch also Engine cutoff /big red switch and starter button and all good).... off to follow some wires now :(

Checked with a multi-meter and all circuits on the handlebar switch showed working (shows 1 when open and 0 when closed/operating) correctly.

[Darkness]

Do the handlebar switch cables have a block connector behind the headlight on the S4? Worth checking, as is the state of the wiring around the headstock.

[LVC]

Do the handlebar switch cables have a block connector behind the headlight on the S4? Worth checking, as is the state of the wiring around the headstock.

Yes they do and am checking that ATM along with the continuity on the rest of the wires :biggrin:

[LVC]

Well what a chuffing PITA that was ....

Good old Ducati had changed the wiring between my 2001 S4 and the Workshop manual I have for the 2002 S4 ..... and what had they changed ..... they have removed the stupidly, stupid capacitor/diode/piece of crap thingy that is hidden in the wiring loom on the side light circuit from the switch.

By pure luck I cut into the "bulky part" of the loom just behind the head stock to find than either side of a well hidden "lump" on the side light circuit I was getting no continuity ..... offending item bypassed as a test and all works ..... so now has been permanently removed and the two ends of the wire correctly connected and all is good again ..... you have got to love 18 year old dodgy italien electrics :freak: :flag:

For those interested here is the chuffing part that is dead and causing all the problems ....

https://i95.servimg.com/u/f95/12/39/65/39/elec_010.jpg

https://i95.servimg.com/u/f95/12/39/65/39/elec_012.jpg

https://i95.servimg.com/u/f95/12/39/65/39/elec_011.jpg

https://i95.servimg.com/u/f95/12/39/65/39/elec_013.jpg

Thanks all for your help - we got there in the end :ukm:

[350TSS]

what was the purpose of the diode in the original design, does anyone know?

[Darren69]

I'm not sure of its function in this instance but it doesn't look like a factory fitted part to me, it looks a bit home brewed tbh.

[LVC]

what was the purpose of the diode in the original design, does anyone know?

I'm not sure of its function in this instance but it doesn't look like a factory fitted part to me, it looks a bit home brewed tbh.

I wondered that but as the only 1 other previous owner definitely didn't add it (he was just about capable of adding petrol) it's a bit strange where it can from - there's a bunch of other "connections" in the same place but just look like a standard branching of a wiring loom - don't seem to be any other diode/thingies anyway.

I'll add it to the list of other "weird" stuff that this bike has got - sure it was a prototype for bad ideas :fiery:

[Albie]

Well what a chuffing PITA that was ....

Good old Ducati had changed the wiring between my 2001 S4 and the Workshop manual I have for the 2002 S4 ..... and what had they changed ..... they have removed the stupidly, stupid capacitor/diode/piece of crap thingy that is hidden in the wiring loom on the side light circuit from the switch.

By pure luck I cut into the "bulky part" of the loom just behind the head stock to find than either side of a well hidden "lump" on the side light circuit I was getting no continuity ..... offending item bypassed as a test and all works ..... so now has been permanently removed and the two ends of the wire correctly connected and all is good again ..... you have got to love 18 year old dodgy italien electrics :freak: :flag:

For those interested here is the chuffing part that is dead and causing all the problems ....

https://i95.servimg.com/u/f95/12/39/65/39/elec_010.jpg


https://i95.servimg.com/u/f95/12/39/65/39/elec_012.jpg

https://i95.servimg.com/u/f95/12/39/65/39/elec_011.jpg

https://i95.servimg.com/u/f95/12/39/65/39/elec_013.jpg

Thanks all for your help - we got there in the end :ukm:
There is no way that's factory fitted by the soldering for a start. Maybe he thought wiring poor standard in first place. Thought he knew better. I think not so.
Glad its sorted now.

[Flip]

Well diodes are usually there to protect something- in this case something behind the Anode (non banded) side.

So where does that wire go to on the Cathode side (banded) and back to on the Anode?

My worry would be that it is there to protect the switch from getting direct voltage to it if it is switching the ground.

[Darren69]

I'm sure I have a pdf copy of the S4 '01 factory manual filed away somewhere, which I may be able to send you. Mine's an '02 and you're right they did make a few changes to the wiring as the ECU was slightly different from '02 on.

[LVC]

There is no way that's factory fitted by the soldering for a start. Maybe he thought wiring poor standard in first place. Thought he knew better. I think not so.
Glad its sorted now.

Yes it is pretty badly done - glad it's not OEM then I don't have to replace it :flamed:

Well diodes are usually there to protect something- in this case something behind the Anode (non banded) side.

So where does that wire go to on the Cathode side (banded) and back to on the Anode?

My worry would be that it is there to protect the switch from getting direct voltage to it if it is switching the ground.

Yes i wondered that as I've LR90 that used to burn out it's headlight switch due to the current running through them but this is the sidelight circuit so really low powered anyway ... weird one :freak:

Downstream side is the switch connector and then handlebar switch itself, upstream I haven't investigated further as it's all covered.

It is however now a permanent live with the ignition on from the 15A fuse in the fuse box (marked for lights).

I can always fit another diode ..... what do you guys think ?

[LVC]

I'm sure I have a pdf copy of the S4 '01 factory manual filed away somewhere, which I may be able to send you. Mine's an '02 and you're right they did make a few changes to the wiring as the ECU was slightly different from '02 on.

That would be most kind if possible ... Wetransfer is good for stuff like that and my email address is tony@wellsdomain.com :biggrin:

[LVC]

Now even more confused as I've just checked diode orientation and the cathode line is on the switch side of the diode .... which, unless I've got it wrong, means that the flow is from the fuse box towards the switch so the diode would only prevent a reverse flow back to the fuse box. So it wasn't/can't protect the switch from having a live current through it ?????

https://cdn.techterms.com/img/sm/diode_1244.jpg

https://i95.servimg.com/u/f95/12/39/65/39/elec_012.jpg

[Flip]

We need to know where that blue wire physically starts (the fuse-if so which one and is it the correct rating?)and finishes (side light bulb?) and what if anything it passes through (the switch?).

[LVC]

We need to know where that blue wire physically starts (the fuse-if so which one and is it the correct rating?)and finishes (side light bulb?) and what if anything it passes through (the switch?).

I assume it starts at the 15A lights/indicators fuse in the fuse box (as pulling this fuse stops the current through the blue wire) and I know it ends at the handlebar switch (pretty certain it's the sidelight circuit there as I was getting continuity on the main beam side but not sidelight side from the switch to the headlight connector until I bypassed the diode).

Note: Sidelight circuit has to be on first for the main beam to come on via the handlebar switch.

[Darren69]

That would be most kind if possible ... Wetransfer is good for stuff like that and my email address is tony@wellsdomain.com :biggrin:

I just checked and it is the '02 one that I have not the '01, so same as the one you have. Sorry.

[LVC]

I just checked and it is the '02 one that I have not the '01, so same as the one you have. Sorry.

No worries thanks for looking (I haven't been able to find one for a 2001 hence why I have the 2002 .... will keep looking) :mand:

[Luddite]

There's a 2001 S4 owners manual (91370601F - printed 01/2001) on issuu with a wiring diagram on page 78, which might help.

https://issuu.com/marcoslara5/docs/ducati_monster_s4_2001_owner_s_manu/78

[LVC]

There's a 2001 S4 owners manual (91370601F - printed 01/2001) on issuu with a wiring diagram on page 78, which might help.

https://issuu.com/marcoslara5/docs/ducati_monster_s4_2001_owner_s_manu/78

Thank you, yes this confirms what I thought - fuse box to switch with no diode - still can't see why anyone added it though but won't be putting one back unless I discover a really good reason to.

[350TSS]

Could it be anything to do with an alarm system. The quality of the soldering /joining looks nearly as bad as the alarm system fitted to my ZX9R when i bought it second hand.

[LVC]

Could it be anything to do with an alarm system. The quality of the soldering /joining looks nearly as bad as the alarm system fitted to my ZX9R when i bought it second hand.

There isn't an alarm, just the factory immobilizer .... absolutely no idea why it was added :banghead:

[Luddite]

Have a look at the thread Lucaz started on the Ducati Forum, particularly the picture in post #3.

https://www.ducatiforum.co.uk/threads/any-idea-what-is-this-for.4933/

It's a diode to stop a voltage spike travelling back down the loom when the starter solenoid disengages. Does your bike have one in the same place? If not, I'm wondering if yours was moved, as some posts suggest Ducati relocated it further up the loom to protect it from damage.

[Flip]

Yes I can see that- just looking through the schematic of my 1997 900 and it's there across the solenoid terminals and I can see why it could be on the blue wire (assuming it is the same of course but we all know what assumption is) from the light switch as that is directly from the 7.5A fuse D4 (turn signals, side, tail and warning lights) and then there is a return wire from the light switch back to the ignition switch where the side light circuit (with ignition on) picks up from the Parking light circuit (steering lock on).

But crucially there is the wiring from the ignition switch through to the General Relay, Fuses, Battery and Starter Solenoid (and obviously going to the Starter and Kill switches) which is all live with the ignition on thus the reason for the diode to protect it all.

You can also see from the schematic why (although it seems to vary bike to bike) that the General relay arcs so badly (speeding up its' demise) from the charge in the coils when you switch the motor off using the key.

Whereas using the kill switch to stop the motor running prevents this while the switch contacts remain unaffected.

If you're intrigued by that, prise the yellow cover off the relay and see if the contacts spark over when you turn the motor off with the key, then try it again using the kill switch.

[LVC]

Have a look at the thread Lucaz started on the Ducati Forum, particularly the picture in post #3.

https://www.ducatiforum.co.uk/threads/any-idea-what-is-this-for.4933/

It's a diode to stop a voltage spike travelling back down the loom when the starter solenoid disengages. Does your bike have one in the same place? If not, I'm wondering if yours was moved, as some posts suggest Ducati relocated it further up the loom to protect it from damage.

Thank you .... that now makes much more sense and I'm wondering whether it was a retrofit/modification done at the dealers rather than the factory .... judging by the state of the soldering ?


Yes I can see that- just looking through the schematic of my 1997 900 and it's there across the solenoid terminals and I can see why it could be on the blue wire (assuming it is the same of course but we all know what assumption is) from the light switch as that is directly from the 7.5A fuse D4 (turn signals, side, tail and warning lights) and then there is a return wire from the light switch back to the ignition switch where the side light circuit (with ignition on) picks up from the Parking light circuit (steering lock on).

But crucially there is the wiring from the ignition switch through to the General Relay, Fuses, Battery and Starter Solenoid (and obviously going to the Starter and Kill switches) which is all live with the ignition on thus the reason for the diode to protect it all.

You can also see from the schematic why (although it seems to vary bike to bike) that the General relay arcs so badly (speeding up its' demise) from the charge in the coils when you switch the motor off using the key.

Whereas using the kill switch to stop the motor running prevents this while the switch contacts remain unaffected.

If you're intrigued by that, prise the yellow cover off the relay and see if the contacts spark over when you turn the motor off with the key, then try it again using the kill switch.

That's interesting .... so from now on I should shut her down with the kill switch ?

and probably best to put another diode back into the same place and same orientation?

The text stamp on mine reads "6A05" which seems to correspond to diodes I've found on ebay for about £4 for x5

[gemantsdad]

Hi, from the Handbook, " Warning- this switch is mainly intended for use in emergencies when you need to stop the engine quickly"

[Flip]

Thank you .... that now makes much more sense and I'm wondering whether it was a retrofit/modification done at the dealers rather than the factory .... judging by the state of the soldering ?




That's interesting .... so from now on I should shut her down with the kill switch ?

and probably best to put another diode back into the same place and same orientation?

The text stamp on mine reads "6A05" which seems to correspond to diodes I've found on ebay for about £4 for x5

Personally I would try and prise the yellow cover off the General Relay to have a look at what goes on before worrying about it- it certainly doesn’t seem to affect all bikes. I only found it because soon after buying my bike it seemed to eat relays. A couple of ‘bleed resistors’ can solve the issue but that’s a whole ‘nother thing.

But yes I would definitely look at getting the diode back in the circuit somewhere- they are cheap enough but if you have trouble let me know- we’ve probably got some at work. In addition I would use some heat shrink sleeve over it to give it a little more protection.

Hi, from the Handbook, " Warning- this switch is mainly intended for use in emergencies when you need to stop the engine quickly"

Yeah that’s simply because in an ‘emergency’ your fingers are a lot closer to the kill switch than they are fumbling around with the ignition key.

The ignition switch is simply a way of making turning it on and off secure so only the owner (in an ideal World) can operate it- many old classic bikes (along with competition machines) don’t have keys.

[LVC]

But yes I would definitely look at getting the diode back in the circuit somewhere- they are cheap enough but if you have trouble let me know- we’ve probably got some at work. In addition I would use some heat shrink sleeve over it to give it a little more protection.

Thx, would this one work ?

ebay item number : 113688671255

[Flip]

To be honest I’m a little confused as to why they used a 6amp rated diode when, if the blue wire on your bike is the same as mine and on a 7.5amp circuit. Or if like you thought, is the wire for the headlight and therefore on a 15amp circuit making it an even worse choice.

It is still worth finding out which fuse that wire actually goes to just for future knowledge but I think I would be looking at a higher rated diode such as this:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F 192608781257

These are basically the same kind of ‘blocking’ diode used on those little battery charging solar panels to prevent the battery sending voltage to the panel instead of the other way round.

[LVC]

To be honest I’m a little confused as to why they used a 6amp rated diode when, if the blue wire on your bike is the same as mine and on a 7.5amp circuit. Or if like you thought, is the wire for the headlight and therefore on a 15amp circuit making it an even worse choice.

It is still worth finding out which fuse that wire actually goes to just for future knowledge but I think I would be looking at a higher rated diode such as this:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F 192608781257

These are basically the same kind of ‘blocking’ diode used on those little battery charging solar panels to prevent the battery sending voltage to the panel instead of the other way round.

It's on the 15A fuse marked as "Tail Light + Turns + Pilot Light" - 3rd up from the bottom on the box. The 7.5A one above it is for "Passing".

Your choice makes more sense to me, thx :mand:

[Luddite]

It would be interesting to see what the actual current draw on the blue wire is. After cutting the wire but before attaching the diode, you could put a multimeter set to amperes between the two ends and see what it reads with the indicators, pilot and tail lights on.

[Flip]

It's on the 15A fuse marked as "Tail Light + Turns + Pilot Light" - 3rd up from the bottom on the box. The 7.5A one above it is for "Passing".

Your choice makes more sense to me, thx :mand:

I’m still not convinced the turn signal circuit should be on a lower current circuit than the headlight.

I checked on my YZF600R and the turn signals etc. including the fuel pump is on a 15amp fuse whereas the headlight is on a 20amp but the pattern is the same as my Monster.

https://i.postimg.cc/85tDFpnt/369-CC056-8-BC8-4301-AFF4-BAD7-F8414-D95.jpg (https://postimg.cc/xJJBh2Qz)
https://i.postimg.cc/j22TPppK/EBA8E8AC-C2CF-47ED-8322-87CFFEFBA7CC.jpg (https://postimg.cc/Ppg0kRfF)

Perhaps someone else with an S4 could have a look at their fuse box to confirm or deny my theory?

It would be interesting to see what the actual current draw on the blue wire is. After cutting the wire but before attaching the diode, you could put a multimeter set to amperes between the two ends and see what it reads with the indicators, pilot and tail lights on.

Yes I agree and I am sure it is pretty conservative but it wouldn’t be the first time Ducati have used rather marginal wiring on their motorcycles but either way I still don’t understand why a lower current rated diode would be used as if it’s having to work (which presumably it is) it’s only going to keep getting hot and eventually fail as this one did.

Excess heat on the rectification (diode) side is exactly why we get failures in the shunt type regulator/rectifiers.

[Luddite]

Perhaps someone else with an S4 could have a look at their fuse box to confirm or deny my theory?

Now, we all know that Ducati owner's manuals can't always be taken as gospel but this is what the 2001 S4 one shows...

https://i.postimg.cc/8PW3gdzZ/wp-ss-20190810-0001-2.png (https://postimages.org/)

https://i.postimg.cc/nLwTDMLs/wp-ss-20190810-0002-2.png (https://postimages.org/)

The blue wire goes into the fuse box at number 14 and the 6-14 fuse should be 15 amps.

[LVC]

Yes indeedy ....

https://i95.servimg.com/u/f95/12/39/65/39/fuse_b10.jpg

Thanks @Flip for explaining why it burnt out .... makes sense if it is only 6A :banghead:

and many thanks to both of you for taking the time to help - glad to see the willingness to assist is still alive after all the years :mand:

I will order one of the diodes suggested at the correct rating and add it back into the circuit where the old one was and then I may even change the insurance to road use (rather than storage) and actually take her for a spin or two :flag:

[Flip]

Now, we all know that Ducati owner's manuals can't always be taken as gospel but this is what the 2001 S4 one shows...

https://i.postimg.cc/8PW3gdzZ/wp-ss-20190810-0001-2.png (https://postimages.org/)

https://i.postimg.cc/nLwTDMLs/wp-ss-20190810-0002-2.png (https://postimages.org/)

The blue wire goes into the fuse box at number 14 and the 6-14 fuse should be 15 amps.

Yes very true- thanks for posting that up.
It would interesting to know whether the headlight is on the 20amp circuit of the injectors and coils etc. thus following the same pattern at least.

Yes indeedy ....

https://i95.servimg.com/u/f95/12/39/65/39/fuse_b10.jpg

Thanks @Flip for explaining why it burnt out .... makes sense if it is only 6A :banghead:

and many thanks to both of you for taking the time to help - glad to see the willingness to assist is still alive after all the years :mand:

I will order one of the diodes suggested at the correct rating and add it back into the circuit where the old one was and then I may even change the insurance to road use (rather than storage) and actually take her for a spin or two :flag:

Glad we helped a bit, it’s always difficult trying to diagnose without actually being able to trace the wires etc. and even harder without a diagram to follow.

Now get it sorted and enjoy it on those lovely French roads around there.

[LVC]

Righto chaps .... postie delivered the new Diode today (and his 9 brothers .... for £0.90 for 10 what could I do ^^) so tomorrow is soldering day .... it's not going to be neat but hopefully it'll function and I'll hide it all under heat shrink once we're good :rolleyes:

Look out Frenchie roads the beast is back :pedro:

[LVC]

Well it wasn't far and it wasn't fast but for the first outing she's had in over 4 years ..... god it felt good :thumbsup::spin:

https://i95.servimg.com/u/f95/12/39/65/39/69481910.jpg

https://i95.servimg.com/u/f95/12/39/65/39/69997910.jpg

https://i95.servimg.com/u/f95/12/39/65/39/69543910.jpg

Thanks all for your help :cool:

[Flip]

Glad you got it sorted and good to see it up and running in the lovely looking French Sunshine. :D

[LVC]

Glad you got it sorted and good to see it up and running in the lovely looking French Sunshine. :D

Cheers :thumbsup: