Article [13] ST1300 - Headlight Circuit

Yes they do - exactly as you describe. Follow the link in the post above yours and scroll down to post #20.
They do it by injecting current from a different source into the high beam circuit. Otherwise with all 4 filaments powered, there would be an overload.
(See the circuit diagram at the top of the same thread)
So I followed the link to this thread @jfheath , thanks. Very helpful.

Unfortunately as I've perused one of my usual real world research sites - *cough* ebay *cough* - it appears that the EU and NA versions of the left bar switch assembly appear to have different connectors 'at times'.

A listing out of the Netherlands with a passing switch shows two connectors - 9-pin, black (populated with 8 pins) and 6-pin white (populated with 6 pins).

Honda ST 1300 Pan European 2002-2014 Handlebar Switch Left (Handlebar sw201388995

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A comparable switch assembly from North America without the passing switch shows two connectors - 9-pin, black (uncertain population) and 9-pin red (uncertain population). Few sellers had the good manners to include a good photo of the open end of the connectors and their pins like the one above. And I'm too hot and tired at the moment to catalog the variations I encountered. There were however enough other listings with photos to confirm that the red connector on the NA version is a 9-pin, not 6 like the EU one above. I made sure to disregard 2003 switchgear without the windshield control; of which there was at least one or two in my search.

2003-2013 Honda ST1300 ST 1300 Right Handlebar Engine Start/Stop Switches

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So I guess it's not as easy an enhancement as I hoped. :(
 
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I can't see the pictures.

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In UK, Left hand switch was different according to whether it was the ABS deluxe model with windshield adjuster or not. I think the adjuster was available in some places on the STD model.

There's also the issue of where you feed the power from. The Uk model has a separate fuse.
I suppose the thing to do is describe what you have for your present unit. When I can see the pics, I might be able to help to work it out.
 
I can't see the pictures.

1624775846638.png

Left hand switch was different according to whether it was the ABS deluxe model with windshield adjuster or not. I think the adjuster was available in some places on the STD model.

There's also the issue of where you feed the power from. The Uk model has a separate fuse.
I suppose the thing to do is describe what you have for your present unit. When I can see the pics, I might be able to help to work it out.

Aww, shoot, the images didn't stick. I'll try to fix, but yes I'll look at my own connectors when I next peel back the tupperware.
 
Aww, shoot, the images didn't stick. I'll try to fix, but yes I'll look at my own connectors when I next peel back the tupperware.
Try again. By the way, I made sure to only consider switch assemblies that had the windshield adjuster.
 
The relay grounds go through the yellow, multiway ground connector near the right hand mirror fixing bracket, behind the headlight. The headlight grounds do not.

If the headlights don't ground through the yellow connector, where do they ground?

I read this thread while trying to figure out the problems I was having, and I'm still confused about this point. Looking at the wiring diagram, it sure seems to me that both headlights have to ground through the yellow connector. In fact, it seems to me that it's the other way around: the relays ground more directly to the frame, under the gas tank, while the headlights ground through the yellow connector behind the cowl/windshield/headlight.
 
The relay grounds go through the yellow, multiway ground connector near the right hand mirror fixing bracket, behind the headlight. The headlight grounds do not.

If the headlights don't ground through the yellow connector, where do they ground?

I read this thread while trying to figure out the problems I was having, and I'm still confused about this point. Looking at the wiring diagram, it sure seems to me that both headlights have to ground through the yellow connector. In fact, it seems to me that it's the other way around: the relays ground more directly to the frame, under the gas tank, while the headlights ground through the yellow connector behind the cowl/windshield/headlight.

Hmm. Thank you. I have made an assumption that the yellow multiway connector has always been part of the ST1300.
I've also used the circuit diagrams that @SpikingJC contributed - which show the yellow multiway connector.
My article did comment that the wiring diagram that I produced for the headlights related to the UK ST1300A9.

What year is your bike ? My comments might not apply to your model.

However - I made a mistake. According to the SpikingJC diagram the earth to the headlights takes a different route to earth from the one taken by the earth for the relays.

This is true for the 2008 model and later, according to the diagram - but not for the pre-2008 models.
But none of those earth leads pass through the 14P yellow connector.

Headlight earth (Green) passes through the 24P white connector on its way to the earth under the rear of the petrol tank.
Post 2008 models, the relay earth passes through a 20P Pink joint multiway connector - which is also connected to the main earth under the tank.

Pre 2008, there is no yellow joint connector shown on any diagrams that I have seen and the relay and headlight earths are connected via the same cable.

I suspect that the circuit diagrams lag behind what was happening with the various models. The wiring may have been spliced into the main loom originally, and later additional multiway connectors were added.

Whatever - my statement that the relay earth wires passed through the yellow connector were not correct. They pass through a different multiway connector from the one used by the headlight earth (2008 on) but it isn't the yellow one. Not according to the coloured diagram.

I tried to find the wire that provides the earth to the yellow mulitiway connector ! It seems that all of the devices connected to that are controlled by an earth provided by the ECU. Presumably these are devices that need to be switched off in the event of eg a tip over. This yellow connector has only B/W leads going to it and it connects to various relays and injectors. But not the headlight relay as I first stated.

I wonder if one of the other connectors is also yellow ? I don't know.
 
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What year is your bike ? My comments might not apply to your model.

However - I made a mistake. According to the SpikingJC diagram the earth to the headlights takes a different route to earth from the one taken by the earth for the relays.

Mine is a 2005. I'm looking at the SpikingJC '03 - '07 Standard diagram because the one in the FSM is tiny and I've found at least one error in it.

I don't see the yellow "joint connector" in the SpikingJC diagram. I don't see it in the FSM's '04 - '07 Standard diagram, either, even though I'm pretty sure that it's there, from what I've read.
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The FSM's '04 - '07 Deluxe diagram shows a 4-pin Yellow "joint connector" connecting black/white wires, and a 20-pin Pink "joint connector" connecting various green wires, but it shows these being aft of the 24-pin connector that's behind the left fairing panel.
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Mine is an '05 model with ABS and the electric windshield, so I assume that's a 'Deluxe', right? The FSM diagram just seems completely wrong.

Based on what I've seen on my bike, I think everything forward of the 24-pin connector grounds through the yellow "joint connector", then through the 24-pin connector, then to the frame under the tank. I think everything aft of the 24-pin connector, such as the relays, grounds via normal wire spices within the wiring harness, then to the frame under the tank. Of course, I haven't ever unwrapped an ST1300 wiring harness, but I think the usual Honda method is to splice wires together using barrel crimps, like this (from CycleTerminal.com):
splice-crimp-3x16.jpeg
 
Thanks for that @gummycarbs . I have never seen that circuit diagram. I have the 04 addendum of the Honda service manual, which includes the wiring schematic. It doesn't show this.

I don't believe that there was an 05 model in the Uk. Check the paint code label on the frame under the seat. Yours is probably on ST1300 A4. But same diagram still applies.

Yes, ABS and electric windshield is the deluxe model.

That yellow 4P connector must be labelled incorrectly as it clearly has 14 pins !

Splices - yes that is my observation from a dismantled 1100 harness. The earth lead is festooned with crimps like that.

It looks like that diagram matches the coloured one posted by SpikingJc.

But I have never matched the wiring on my bike with the wiring diagram as far as earths are concerned. I just checked the wire colours at the headlights and relays.
 
Check the paint code label on the frame under the seat. Yours is probably on ST1300 A4. But same diagram still applies.

Mine says ST1300A5, whatever that means.

That yellow 4P connector must be labelled incorrectly as it clearly has 14 pins !

Yeah, they dropped the leading '1'. Also, if you look to the right of it, you'll see the 'option' terminal wires are mislabelled. It shows a second W/G wire when it should actually show a second R/G wire. I think maybe they put an intern on the task of finishing up the documentation...

Regarding spices, now I'm starting to rethink that assumption after looking into the 20-pin pink "joint connector". Maybe they did this weird joint connector thing everywhere. Never seen it before on any Honda, but this is the newest Honda I've owned.
 
ST1300A5 decoded

ST1300 = ST1300
A = ABS / Deluxe model
5 = model year ( not the year of manufacture). 2005. When the run out of digits, they start using letters. So 9 = 2009, A=2010, C=2012.

The same year code is used in the VIN stamped on the headstock. 10th character.

In the UK for the ABS models we had only A2, (A3), A4, A6, A8, A9 and AE. - not sure about A3 !

I know USA had an AC model. I've never come across anyone with an A5 before

That didn't mean that they stopped building them in the intervening years - it just meant that they hadn't changed the specification since 2009. I know that my A9 model came off the production line mid September 2013. Shortly after they were producing the AE 2014 specification.
 
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