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Turn Indicator Switch Question

zanthor

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So going through the things that aren't working right on my 1978 CB750 I found that the turn signals don't blink. I assume this has something to do with the relay either being bad or the bulbs not drawing enough juice, I have a few things to try to fix it... but I was looking at the wiring diagram I'm VERY confused by whats there...

IMG_3110.JPG

What does it mean by 'Left 1' and 'Left 2'? My switch only feels like it has 3 positions (left/neutral/right), and I certainly don't hear a turn signal buzzer, but the horn doesn't work either so it's quite possible that just doesn't work.
 
I dont know what Left 1 and Left 2 are referring to as I suck at electronics but have you replaced the old thermal flasher for the turn signals? This happened to me where the signals would turn on but not blink, and I replaced the flasher with a new one from advance auto (only about $12) and it fixed the problem immediately. Hopefully it's that easy for you as well.

This thread has a picture of the packaging, model 552:
http://honda-cb750-s.456789.n3.nabble.com/2-wire-aftermarket-turn-signals-td4037525.html
 
So going through the things that aren't working right on my 1978 CB750 I found that the turn signals don't blink. I assume this has something to do with the relay either being bad or the bulbs not drawing enough juice, I have a few things to try to fix it... but I was looking at the wiring diagram I'm VERY confused by whats there...

View attachment 3900

What does it mean by 'Left 1' and 'Left 2'? My switch only feels like it has 3 positions (left/neutral/right), and I certainly don't hear a turn signal buzzer, but the horn doesn't work either so it's quite possible that just doesn't work.

I think I have a little help to offer. Keeping in mind the bike is setup so only the front indicators are running lights and the rears only blink. That is standard Honda setup.
So the front indicators have 2 contacts and a ground where the rear only has one contact and a ground. The front bulbs have 2 filaments and the rears have 1.
The brown/white is power, even though the fuse it comes from says “taillight”
that circuit powers the indicators too. Notice how the brown/white portion of the switch has all black dots. Let’s call that the power contact strip.
In the neutral position the power contact strip only sends juice to the front left and right indicators (1 filament) as running lights.
Refering to the owners manual you will see the indicator switch actually has 2 modes for each direction. One where you just nudge and hold (left and right 1), and one where you push it all the way over (left and right 2). The only difference is that 1 does not engage the buzzer and 2 does. The buzzer is not needed for the circuit to work, I removed mine cause it’s annoying.

Where there is a black dot it means that circuit is bridged or engaged.

So when you switch to the left what happens is the switch has to let the right front running light stay on (blue/white), but it turns the left front running light off (orange/white) which is the 1st filament, so the winker relay can blink the 2nd filament in the front bulb and the only filament in the rear bulb using the solid orange wire.

For the right it’s the reverse.

Hope this helps. I’m no expert though.
Are they stock indicators?
Daren.
 
The nudge/switch makes sense, I had noticed that but thought it was an old squishy switch not a feature.

I have no idea if they are stock indicators :), pictures are here.

Oddly enough the right side now flashes, the left does not... I haven't changed anything other than riding it a little.
 
testing wiring harness

The nudge/switch makes sense, I had noticed that but thought it was an old squishy switch not a feature.

I have no idea if they are stock indicators :), pictures are here.

Oddly enough the right side now flashes, the left does not... I haven't changed anything other than riding it a little.

Those look like stock to me.
When electrical issues become intermittent it's usually a good bet you have breaks in wires or shorts which through movement of the bike either make contact one day and don't the next. The grounding on these older bikes is usually suspect, and at the ends of the wires where they meet the connector.
Sometimes the connectors are grungy and contact is intermittent. After years of possibly being connected and disconnected they tend to break. Unfortunately your best bet is to get a multimeter and print out the wiring diagram to a larger format so it's easier to read out by the bike. Find the start and end of every wire that has to do with your issue, connect the multimeter on the ohms setting to either end and jiggle the wires. If the needle jumps up and down you have a bad wire at one end. To determine which end is bad take a pin and pass it thru the wire a couple of inches away from the connector and connect the multimeter to the pin and the connector and jiggle again. Alligator clips come in very handy here. To test the switch connect one end of the multimeter to the brown/white inside the bucket, then move the switch to the left or right position and test every wire which has a black dot on it in the wiring diagram. Once again jiggle the switch to see if the needle jumps up and down. Sorry this is so long, hope it helps
It's a lot of work but one of the few ways I know how to track down wiring issues, usually a couple of coldies help.
Good luck.
 
My indicators blink on position 1 (both left and right) but on position 2 they are constantly lit. does this indicate a problem with the brown/blue wire?
 
Have you tried another winker? Sorry for the delay but I've been busy. The brown and blue is only for the buzzer and not important to the circuit. Try to unplug the buzzer and see if your blinkers work. Good luck. If I think of anything else I will post.
 
Daren, I dont know you but you are the man.

pulling the wire fixes the blinkers.

Thank you ever so much.
 
I'm glad I could be of help, sometimes I know what the hell I'm talking about....but not often like my post about my clutch and gears. Did I ever get that wrong and probably confused everyone including myself. I really had my head up my exhaust on that topic.
I have heard but can't verify that the older the winker relay, the more juice it may need to function.
In position number 2 the circuit needs to feed the winker AND the buzzer, so the winker relay doesn't get enough juice to actually wink and the buzzer may not buzz.
A new winker may be the solution if you want to use the buzzer too. There are cheap alternatives from the auto parts store to replace the winker relay, it need not be a Honda specific part.
Riding in Iceland must be beautiful, how are the roads? How many months out of the year do you get to ride?
daren
 
It depends greatly on the wet her each year. At least 8 are doable but there are 4 that are good. Roads are for the most parts pretty good.
 
My indicators blink on position 1 (both left and right) but on position 2 they are constantly lit. does this indicate a problem with the brown/blue wire?

I have this same issue, except it's just on my right side. What fixed the problem for you? I already replaced the winker relay with an LED one. Any suggestions would help! Thanks!
 
So going through the things that aren't working right on my 1978 CB750 I found that the turn signals don't blink. I assume this has something to do with the relay either being bad or the bulbs not drawing enough juice, I have a few things to try to fix it... but I was looking at the wiring diagram I'm VERY confused by whats there...

View attachment 3900

What does it mean by 'Left 1' and 'Left 2'? My switch only feels like it has 3 positions (left/neutral/right), and I certainly don't hear a turn signal buzzer, but the horn doesn't work either so it's quite possible that just doesn't work.
I can tell you how I've tried to figure those domino schematics out, but what I learned is that it all comes down to connectivity that you can get your head around. Check the cables for voltage. It means taking out a few things -- maybe several times --- but it's the only way to keep it out of the shop( $$$$).
 
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