OzSTOC
Honda ST1300 Section => Electrics & Electronics - Volts, Amps and Fuses ST1300 => Topic started by: cravenhaven on September 02, 2018, 09:50:18 PM
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What were Honda thinking when they designed the wiring for the headlights?.
I have a problem with the headlights staying on high beam regardless of the switch, which I thought may have been caused by a faulty Chinese LED headlight shorting the high and low beam circuits. Upon examination of the fault and study of the wiring diag I discover that the headlight switch operates the RHS headlight directly and the LHS headlight via a pair of relays.
Does anyone have an explanation of why they would do that?
Allan
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Without seeing the wiring diagram, I'll be guessing.
If the switch is of a high enough rating to run one headlight but not 2, that could be a reason.
Another reason may be local automotive wiring rules. My logic being, it would guarantee at least one light working if the relay failed.
Another could be a misinterpretation of the wiring diagram. It wouldn't be the first time I've misread a wiring diagram. It's easy to follow a wire and jump to the wrong one and continue following the wrong one.
Sent from my SM-G930F using Tapatalk
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As far as headlight wiring goes you have a separate relay for low and high beam (from the manual). Power is fed from the battery via the start switch (except Police) to the Hi/Lo switch.
Both relays are fed from the same circuit back battery via the Fuse block but only one relay will be active depending on the Hi/lo switch position.
I have the 1100 Police front light circuits in colour and they match the ones in the 1300 manual I have. The basic light wiring circuits are the same on both 1100 and 1300 and probably a Honda standard anyway.
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Thanks guys,
You're quite right Gary, these wiring diags are difficult to follow so I copied it to mspaint and coloured the relevant connections.
Thanks Alan but if you look at the "colour enhanced" diagram I have attached from my workshop manual, you can see that the Right headlight is powered directly from the switch which also provides the power to the coils of the headlight relays. The Left headlight is powered by the relay contacts, as is the high beam indicator. The red and orange traces show the power sources.
Allan
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Certainly a little different though the partial 1100 diagram I have doesn't look OEM so I might have a look in the manual.
the 2003 1300 manual I have doesn't show the passing switch.
I also find it odd that the LH headlight circuit goes to the aiming switch
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It doesnt go to the aiming control, it goes to the high beam indicator. Its just the way they drew the picture.
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I forgot I had this - 2006 ST1300A coloured wiring - download it as it's easier to read than the OEM ones. Also includes the optional wiring like quartet harness etc.
https://drive.google.com/file/d/1abN5-9caVgdwJtBpdFgAnHqVpKR9m6ak/view?usp=sharing
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Do the low lights come on when selected as well as the high, or just the high.
It sounds like there may be a problem with the hi/lo switch itself.
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Turned out to be a problem with the RHS bulb. It stopped working altogether and the LHS followed the switch operation as it should. When I bench tested the bulb I found it worked intermittently in response to a bump or two.
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