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Motorcycle Turn Signal LED - Unique situation


Super Moderator
Do you have a schematic of the motorcycle wiring system? Is it possible to get one?
Thread starter #42
Thanks, Pommie! That's valuable information.

I took the back of the bike apart again, and let me tell you, it was hell the ruggedest mile getting my fat paw inside that little bitty space trying to fit a caliper in there. But I managed it. And I rechecked it four times. Even with all that contortion, I still couldn't get a depth of either the interior cavity, the exterior, or the length of the actual pins in the interior.

You've all seen the pictures of the actual connector, and the PCB it's on, so here's the very rough sketch I did of the dimensions of the tiny connector. And when I say tiny, I mean TINY. That whole thing is only about 7mm X 5mm on the exterior (not the inside cavity.) The inside cavity is only about 5mm X 3mm, and the pins are only 2mm apart! How the heck anyone can manipulate a plug connection that small is beyond me.


I'm making progress here. Now I just need to find a plug that will fit it.
Thread starter #45
It happened!

One of the emails I sent out to electronics parts places has a guy who took my photos and that sketch, and compared them to the manufacturers' engineering drawings of all the two-pin connectors they have, and found it. The guy actually FOUND IT.

It's called a "ST-PH 2 pin". Comes in two parts, a male socket, which is what I have on my bike, and a female, which is the "plug". The female side of it is even pre-wired with 11" of 26AWG wire.

And get this: The guy was so intrigued by the fact that I'd gone to the trouble I've gone to, he said he would throw two of them into an envelope and send 'em off, no charge!

How's that for dumb luck?

And I couldn't have done it without you guys! A big Thank You to all of you who contributed!!

Now I just have to figure out how to determine polarity.... It's always something!
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Thread starter #46
They came!

The connectors arrived in the mail today!


I am going to try to install them Wednesday (off from work all day) and we'll see how it goes!
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Well-Known Member
Did you verify that they fit the corcuot board connectors? It would be really frustrating to wire them up, only to find that they almost fit!
Thread starter #48
Did you verify that they fit the circuit board connectors? It would be really frustrating to wire them up, only to find that they almost fit!
Considering that they only came today, and the first opportunity I will have to do anything is Wednesday, I'd have to say no. But a test fit before anything else is at the top of the agenda.

I have to admit, rather smugly, that I thought of that all by myself... :D
Thread starter #50
Well.... I did it.

And I couldn't have done it without all you great folks on this forum.

Let me share a few photos and a bit of backstory. This is going to be a long one, so grab your favorite beverage, and sit back.

The connectors arrived Monday, and I knew that with my work schedule, today would be the first opportunity. Early this morning, I dismantled the back end of the bike, to get access to the PCBs for the rear turn signals. I had my wiring diagram handy, and the service manual. Took me a bit of wrangling to get the covers off, so I went and bought a flexible screwdriver. Made it a piece of cake.

Let me tell you, it was hell the ruggedest mile to get those plugs into those sockets. I ended up taking a Dremel tool and carving out the end of a bamboo chopstick to make a holder for the plug so that I could maneuver it into the socket. I also found that there was a very tiny rib along one side, (less than a millimeter or so) preventing the plug from seating properly, so I took an X-acto knife and shaved the rib off. Fit the plug into my homemade installation tool, and it slid right in. Seated perfectly.


I reasoned that since the pumpkin-stalk turn signals already had connectors (of the bullet variety) into the wiring harness, that I could re-use them in this application. So, I removed the stalk turn signals, and clipped off the wiring leaving about 4" of wire and the connector. It was at this point that I decided that I didn't need to leave the covers of the PCBs off any more, so I drilled a 1/10" hole in each one, and threaded the wires from the plugs through them, and reinstalled the covers. I put a bit of silicone over the holes, to prevent water ingress.

It was a simple matter of then determining exactly what the polarity was, and so I took a break, and came in to research it. I found a neat little device on Instructables that enables people to light up for test purposes, 12V LED lights. Made from a power supply from a printer, no less. A couple of alligator clips soldered on, and I was in business.


It so happened (I put it down to blind luck) that the way the plugs fit into the sockets, the red wire was the hot one, and the black wire was the neutral, so all I had to do was attach the correct colored wires with the bullet connectors to the ends of the leads. I think I did a pretty good job, even though I'm by no means an expert at soldering. For the record, I watched a dozen YouTube videos, and practiced on several different wire connections for about an hour before I felt comfortable doing it to the bike.



I kept using my little testing device to check connections at every step of the way, to make sure the LEDs would light, before I'd go to the next step. I used heat-shrink tubing and a heat gun to cover up all the soldered connections, both for added strength and for moisture protection. Can't be too careful when one really doesn't know what one is doing.

It wasn't long before I had connected up everything there was to connect, and reattach the bullet connectors of my leads into the wiring harness. I reconnected the battery, and turned the key, and it actually worked! Un-freaking-believable! And I did it! (with this forum's help and advice!)

Here's an image of the lights lit up.


I wanted to upload a short (11 second) video of the lights working, but I couldn't get it to upload.

Anyway, I wanted to thank everyone for all their advice, assistance, and for the generous and freely given expertise and knowledge.

Thank you all!

Now, on to the front signals... I am still waiting on the housings to be shipped in from Japan... I think they're using an old rowboat to send them...

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