Well, That Doesn't Look Right... (Wiring)

gummycarbs

gummycarbs

Joined
Jun 10, 2021
Messages
47
Age
49
Location
Oregon
The other day I noticed a really bright flash reflected off the minivan in front of me in the turn lane. Killed my turn signal and it stopped. Either gnomes upgraded my turn signal bulb dramatically or something is making my headlight flash.

Sure enough, I've got an occasional bright indicator stuck on, and sometimes the left headlight will flash high in time with the turn signal.

This screams ground-path issue to me, but I've also read about the left-hand headlight relay going bad, so both are on the table.

I dug into the wiring connectors on the left side of the bike and found this unpleasant mess:

20230730_124436.jpg

No idea how there's so much corrosion on those connectors. I haven't found anything like it anywhere else on the bike. In fact, I've never seen corrosion like that on *any* motorcycle. It's the kind of thing I expect to see in a car, in wiring that's right next a lead-acid battery. It seems like Honda packed all the connectors with lithium grease, which I don't like. It's sticky, messy, and doesn't seem to have done its job keeping moisture out. I don't think it's helped any by the orientation of that vinyl boot. Maybe my harness is routed incorrectly, but it seems like that boot collects water like a cup rather than shielding the connectors.

20230730_125147.jpg

I'm like 99% sure that red/green wire isn't supposed to be hanging free like that...

Now to go squint at the FSM wiring diagram.
 
Only 99%? What happened to that last 1? I'd be inclined to pull all the connectors from the plastic (carefully noting where each one went) so that they could be cleaned and examined. You can get tools to compress the little finger (fickle finger of fate?) on the back of the terminal inside the plastic housing and then they slide out the back. Try Cycleterminals.com or easternbeaver.com for replacement male and female spade connectors and tools.

Crimping, Cutting, Soldering and Terminal Pin Tools, From Japan

Automotive electrical tools from Eastern Beaver including crimpers, strippers and cutters.
easternbeaver.com

And yes, I found my connectors to be a sticky gooey mess with all of Honda's grease.
 
As above. Buy plenty of terminals, and get a variety of sizes for different gauge wires. Err on the bigger side if you don't know, you can always snip some of the crimp off beforehand if necessary. You will want enough to practice with and some more to redo when you mess it up.

I thought the green stuff was verdigris at first, but I don't think that it is. I think its spilled fluid that has crystallised.

The shield is supposed to be open end downwards and held in place. One by a clip on the headstock, one by a plastic moulding in the inside of the middle fairing. I don't know off hand which one this is.
 
Am I correct in thinking that's the 9-pin connector that goes to the Quartet harness?

WiringDiagram-OptionConnector.png

I couldn't find it at first because I was looking at the '04-'07 Deluxe wiring diagram (mine is a 2005 ST1300 ABS, so I assume it's Deluxe), which maybe has a misprint:

WiringDiagram-OptionConnector-0407Deluxe-Misprint.png
 
Yes - the Delux version had the ABS and adjustable screen in the UK. I note that one diagram has two W/G, the other has two R/G - but yes, that is the 9 pin connector to which the quartet harness is attached.

I got fed up with the bulk of my quartet harness - it put its 4 connectors nowhere that I could access them easily, so I made my own and got rid of all of that bulk near the protective - if you point the open end downwards - shroud.
 
A couple of pictures of the male connector on the other side. No idea what was going on with this 9-pin connector. I did a basic inspection and cleaning when I installed the Quartet harness back in 2021 and I didn't notice anything amiss. Unless I'm misremembering something, the corrosion on this pin/tab has to have happened since 2021!

ST1300-9PinConnectorCorrosion-1.JPGST1300-9PinConnectorCorrosion-2.JPG

(That's wet with ACF-50, which I used along with a soft brass bristle brush to clean off the corrosion)

Incidentally, here's how the Hondaline heated grips were wired when I first bought the bike. The 9-pin connector appears black because it was wrapped in electrical tape to help retain the loose plugs:

ST1300-9PinConnectorOriginalWiring.JPG

I should've pulled that boot fully back, inspected, and thoroughly cleaned it back when I installed the Quartet harness. Instead, I'm stuck not knowing what condition everything was actually in.
 
gummycarbs said:
The 9-pin connector appears black because it was wrapped in electrical tape to help retain the loose plugs:
Click to expand...
The looseness causes heat, which exacerbates the oxidation, and weakens the metal which causes more heat, and the effect snowballs over time.
 
When I installed my quartet harness last winter, all the connectors had been unmolested. But it was still filthy... not corroded, just dirty.
I did some cleanup at the time.
Of course, by the time I was through plugging my Zumo XT into my new harness, I managed to kill / disable my turn signals and flashers.
Don't be like me.
 
 
gummycarbs said:
A couple of pictures of the male connector on the other side. No idea what was going on with this 9-pin connector. I did a basic inspection and cleaning when I installed the Quartet harness back in 2021 and I didn't notice anything amiss. Unless I'm misremembering something, the corrosion on this pin/tab has to have happened since 2021!

ST1300-9PinConnectorCorrosion-1.JPGST1300-9PinConnectorCorrosion-2.JPG

(That's wet with ACF-50, which I used along with a soft brass bristle brush to clean off the corrosion)

Incidentally, here's how the Hondaline heated grips were wired when I first bought the bike. The 9-pin connector appears black because it was wrapped in electrical tape to help retain the loose plugs:

ST1300-9PinConnectorOriginalWiring.JPG

I should've pulled that boot fully back, inspected, and thoroughly cleaned it back when I installed the Quartet harness. Instead, I'm stuck not knowing what condition everything was actually in.
Click to expand...
That green is accelerated copper oxidation, caused by some sort of acid. Someone spilled battery-acid on your bike?
 
DannoXYZ said:
That green is accelerated copper oxidation, caused by some sort of acid. Someone spilled battery-acid on your bike?
Click to expand...

It would be quite a feat to get acid solely inside that one vinyl boot. No other connector on the bike shows any corrosion. Very weird.

I always use Deoxit on connectors and pack them with 3M silicone grease.
 
Another possibility is wire themselves can wick moisture and liquids down air-gap between wire-strands. This is how Bosch O2-sensors sample outside air as reference. I've seen quite a lot of wiring with green/black wire-disease under insulation due to moisture getting down inside them. So I'll add little dab of solder on top of crimp to seal ends of wiring from moisture. That's why I only use silicon-insulated tinned-wiring to build my harnesses.

CUI-corrosion1.jpg
 
So, after about three weeks in the driveway with the fairing panels off while I waited for parts to arrive, the bike is finally back together.

I replaced both sides of the nine pin 'option' terminal for the Quartet harness. A few wires (mostly on the Quartet side, I believe) had dark corrosion like in DannoXYZ's picture. A knife blade easily scraped it off, revealing bright copper. I've never seen this on any motorcycle, having owned Hondas back to '77. Weird.

Having replaced the nine pin connector and verified that the rest of the left fairing connectors were clean, non-pitted, and not burnt, I found that the initial problem was still there intermittently:
  • Using the right turn signal would (sometimes) cause the high beam indicator to stick on.
  • The right headlight would flash the high beam in sync with the turn signal.
  • Turning off the ignition or flipping the kill switch would temporarily resolve the issue.
  • Raising the windshield from the lowest position also temporarily resolved the issue, but only one time.
Adding auxiliary grounds to both sides of the 24-pin connector, didn't fix the problem:
20230819_120045.jpg

The next most likely culprit was the yellow ground junction block behind the windshield. Five million screws later, and the cowl section was free enough to reach the yellow troublemaker.
20230819_125237.jpg
I don't know if you'll be able to make it out, but plastic around the third terminal from the bottom is slightly discolored. The end of the terminal looked slightly pitted, too. It's hard to tell from the lousy phone camera, but I would say that the rest of the terminals just show some light corrosion on the zinc/tin/whatever plating, while that terminal showed pitting.

Anyway, as you probably know, that's the ONE wire that grounds everything at the front of the bike. CopyingIndian Express's ground jumper method went like this:
20230819_131451.jpg
A quick touch-up with a wire wheel and a smear of flux really helps get the solder where you want it.
20230819_132000.jpg
Trimmed back the cap so it can close.
20230819_134011.jpg
The threads were chased and the bolt cleaned up, then everything was smeared with silicone dielectric grease.

After a couple of hours riding, it appears that all of the electrical issues are resolved.
 
DannoXYZ said:
Another possibility is wire themselves can wick moisture and liquids down air-gap between wire-strands. This is how Bosch O2-sensors sample outside air as reference. I've seen quite a lot of wiring with green/black wire-disease under insulation due to moisture getting down inside them. So I'll add little dab of solder on top of crimp to seal ends of wiring from moisture. That's why I only use silicon-insulated tinned-wiring to build my harnesses.

CUI-corrosion1.jpg
Click to expand...

I’ve seen that first hand on my Aprilia. It was wicking oil up the stator wires and after a long enough ride it would drip from the connector about 8” away from the engine case. Took me a while to figure it out.
 
gummycarbs said:
So, after about three weeks in the driveway with the fairing panels off while I waited for parts to arrive, the bike is finally back together.

I replaced both sides of the nine pin 'option' terminal for the Quartet harness. A few wires (mostly on the Quartet side, I believe) had dark corrosion like in DannoXYZ's picture. A knife blade easily scraped it off, revealing bright copper. I've never seen this on any motorcycle, having owned Hondas back to '77. Weird.

Having replaced the nine pin connector and verified that the rest of the left fairing connectors were clean, non-pitted, and not burnt, I found that the initial problem was still there intermittently:
  • Using the right turn signal would (sometimes) cause the high beam indicator to stick on.
  • The right headlight would flash the high beam in sync with the turn signal.
  • Turning off the ignition or flipping the kill switch would temporarily resolve the issue.
  • Raising the windshield from the lowest position also temporarily resolved the issue, but only one time.
Adding auxiliary grounds to both sides of the 24-pin connector, didn't fix the problem:
20230819_120045.jpg

The next most likely culprit was the yellow ground junction block behind the windshield. Five million screws later, and the cowl section was free enough to reach the yellow troublemaker.
20230819_125237.jpg
I don't know if you'll be able to make it out, but plastic around the third terminal from the bottom is slightly discolored. The end of the terminal looked slightly pitted, too. It's hard to tell from the lousy phone camera, but I would say that the rest of the terminals just show some light corrosion on the zinc/tin/whatever plating, while that terminal showed pitting.

Anyway, as you probably know, that's the ONE wire that grounds everything at the front of the bike. CopyingIndian Express's ground jumper method went like this:
20230819_131451.jpg
A quick touch-up with a wire wheel and a smear of flux really helps get the solder where you want it.
20230819_132000.jpg
Trimmed back the cap so it can close.
20230819_134011.jpg
The threads were chased and the bolt cleaned up, then everything was smeared with silicone dielectric grease.

After a couple of hours riding, it appears that all of the electrical issues are resolved.
Click to expand...
Woohoo!! Great work tracking that down and fixing it!!! :)
 
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