Topic: Switch witch? Voltage leaking...

[alacrity]

Hey folks:

So I have a 78 cb550k with some modifications.  I wanted to be able to switch off the headlight when I wanted to do so, and both the donor bike handlebar switches were f'd up from a P.O. crash (or crashes).   I picked up new/re-pop Left and Right switches for the early CB750/cb500 bikes from YAMIYA in Japan  - the left side has T/s and horn, the right has side has the starter, kill and  off/low/high control.

AND here's the odd thing. It all works perfectly... almost.  Key on, headlight/tailight switch off, I get a little glow of light in the taillight (volt leakage). Key off, headlight switch OFF, I go inside the headlight bucket and disconnect the white, blue and brown/white wires. Let's do the latter first:  The brown/white is now disconnected between the switch and the brown/white source/lead from the harness... and -- weirdness -- the now "loose" brown/white from the switch shows a "little" continuity to ground -- 98 ohms.  IF I then move the switch to low beam, I have FULL short/continuity to ground from the white wire out from the handlebar switch (now connected to a standard 4 pole relay). IF I move it to high beam  - same deal, I have FULL short/continuity to ground from the blue wire out from the handlebar switch (now connected to a second standard 4 pole relay). 

And yet when the bike is on and running, the headlight and switch work correctly in all 3 settings, and the kill switch and starter both work perfectly as well.   I see no fault to ground anywhere on the white, blue or taillight lines if the switch is disconnected. That 98 ohm "leak" shows up at the brown wire feeding the running/taillight if the switch is fully connected.

Is this one of those problems where someone will shine a light on what is happening, say "duh!" and I will palm my head and feel like an eedjit?  Hope so! Should I not care about the voltage leak because I should have the headlight/taillight on when riding anyway? Is there some legacy wiring from the cb550k "always on" system I am not thinking about that allows/causes this (and so I shouldn't be condemning the bar switch?)


Thanks in advance.
(the pic is from yesterday's 120mile ride)...

[alacrity]

bump...  help?
I contacted Yamiya and shimpei said, "We have never heard of this problem with our switches..."

:-(

[HondaMan]

I would suggest this, having had some oddity with those switches on a 750K6 I just finished: unscrew the right (headlight) switch from the bar and try it all again. I found the switch was ever-so-slightly leaking current to the handlebar, and since this one had a powder-coated top triple tree, the bars were not fully grounded, which made a leak path from the START button (now the grounding type, formerly the START button-powered headlight type) to the 'running lights' (Brn/Wht) circuit in the upper switch half. When I made a clean ground circuit, the leakage from the START button (about 0.8 volt) went away. The leakage current then got into the "running lights" section of the headlight switch thru the sneak path of the handlebar, making the taillight glow just enough to see it in a dark corner of the garage. Essentially, the circuit was: power from the START button leaked thru the switch housing (lower half) to the handlebar, to the upper half, to the 'running lights' contact on the upper switch (thru the grease that was dripping from that switch to the bar) and this barely lit the rear tail lamp. Weird...Removing the grease was my first clue: the bulb went out, but the current leak (while less) was still visible via the "current" probes of my DVM: it should have been zero. Removing the switch physically from the bars made the taillight go out and the current went to zero: clamping it back on made it "leak" again. Disconnecting the Black wire at the Start solenoid also made the taillight go out, because there was no power at the START button to leak to the handlebar. While grounding the bars made the "leak" disappear to the meter and taillight, it was draining the system unnecessarily: cleaning the grease and the apparently-conductive black paint from the START button's spring contact area made it go away.

Glad I'm not alone, here...Now I don't feel like Rod Serling was standing in my garage, anymore...whew!

[alacrity]

Is it possible that when disconnected the BR/WHT within the handlebar sub harness is physically touching the bars? Are you measuring this "ground short" on the handlebar side, or the harness side?
--measuring at handlebar side - direct from switch body.   When that is disconnected from harness, the br-w wire in harness is discreet from ground entirely - meaning the short is in the switech

BR/WHT and BRWN are both "jumped" basically when the key is in position 1. The black is disrupted in position 2. But the BRWs have power in both so some glow could also be attributed to the brake light circuit? Maybe one of your brake switches is partially depressed or not fully released (check your rear) and without the main power to the TAIL, the brake bulb is only partially glowing?

I can disconnect front and or rear brake light switches and still get the glow.  Power leak is via brown and br/w line not green/black brake light wiring circuit.
And new info - I also have a slight glow in my t/s indicator bulb when (my Aftermarket LED) signals are off.   The t/s switch and Signal lights otherwise function correctly.  So now I am wondering if the relays (the t/s modulator being a type of relay also), are somehow to blame...  Lemme go isolate those and see.


The head light issue is interesting....

[alacrity]

I would suggest this, having had some oddity with those switches on a 750K6 I just finished: unscrew the right (headlight) switch from the bar and try it all again. I found the switch was ever-so-slightly leaking current to the handlebar, and since this one had a powder-coated top triple tree, the bars were not fully grounded, which made a leak path from the START button (now the grounding type, formerly the START button-powered headlight type) to the 'running lights' (Brn/Wht) circuit in the upper switch half. When I made a clean ground circuit, the leakage from the START button (about 0.8 volt) went away. The leakage current then got into the "running lights" section of the headlight switch thru the sneak path of the handlebar, making the taillight glow just enough to see it in a dark corner of the garage. Essentially, the circuit was: power from the START button leaked thru the switch housing (lower half) to the handlebar, to the upper half, to the 'running lights' contact on the upper switch (thru the grease that was dripping from that switch to the bar) and this barely lit the rear tail lamp. Weird...Removing the grease was my first clue: the bulb went out, but the current leak (while less) was still visible via the "current" probes of my DVM: it should have been zero. Removing the switch physically from the bars made the taillight go out and the current went to zero: clamping it back on made it "leak" again. Disconnecting the Black wire at the Start solenoid also made the taillight go out, because there was no power at the START button to leak to the handlebar. While grounding the bars made the "leak" disappear to the meter and taillight, it was draining the system unnecessarily: cleaning the grease and the apparently-conductive black paint from the START button's spring contact area made it go away.

Glad I'm not alone, here...Now I don't feel like Rod Serling was standing in my garage, anymore...whew!

Thank you Mark!  I am gonna pull the switch apart again tomorrow and see if I can clean it out as you did.  I think you had this exact same problem/cause.  I have had the sich apart a few times, and had the same dysfunctional functions.  I was gonna get another switch, but I bet your suggestion will fix it.   Thanksmagain

[alacrity]

I would suggest this, having had some oddity with those switches on a 750K6 I just finished: unscrew the right (headlight) switch from the bar and try it all again. I found the switch was ever-so-slightly leaking current to the handlebar, and since this one had a powder-coated top triple tree, the bars were not fully grounded, which made a leak path from the START button (now the grounding type, formerly the START button-powered headlight type) to the 'running lights' (Brn/Wht) circuit in the upper switch half. When I made a clean ground circuit, the leakage from the START button (about 0.8 volt) went away. The leakage current then got into the "running lights" section of the headlight switch thru the sneak path of the handlebar, making the taillight glow just enough to see it in a dark corner of the garage. Essentially, the circuit was: power from the START button leaked thru the switch housing (lower half) to the handlebar, to the upper half, to the 'running lights' contact on the upper switch (thru the grease that was dripping from that switch to the bar) and this barely lit the rear tail lamp. Weird...Removing the grease was my first clue: the bulb went out, but the current leak (while less) was still visible via the "current" probes of my DVM: it should have been zero. Removing the switch physically from the bars made the taillight go out and the current went to zero: clamping it back on made it "leak" again. Disconnecting the Black wire at the Start solenoid also made the taillight go out, because there was no power at the START button to leak to the handlebar. While grounding the bars made the "leak" disappear to the meter and taillight, it was draining the system unnecessarily: cleaning the grease and the apparently-conductive black paint from the START button's spring contact area made it go away.

Glad I'm not alone, here...Now I don't feel like Rod Serling was standing in my garage, anymore...whew!

Hey there Mark:  As a reminder, this is a harness off a '77 cb550k to which (we actually, with your help last year), grafted a set of cb500 control switches onto the bike.

OK so here is an update.  I pulled the switch off and cleaned it out.  Even with the switch hanging off the bar,  I STILL have the same problem. Why? because when I installed it, I added a ground wire to the back of the starter circuit/button plate to ensure proper ground with my non-drilled, powder coated bars. So the switch body is fully grounded.  And now I thought it was just grease/crap in the switch body causing this.  So I ordered a replacement cb500/cb750 (71-73 type) right switch from the nice guys at 4into.com  (yes that was a plug).  I wired that one in and guess what? Identical behavior.  The switch when active does all the things you want it to do correctly (as mine does).  It's when it is off that there's a problem...  Disconnecting the switch body from the added ground wire (since I wasn't getting ground from the bars) solves the problem but then the starter button doesn't work. SO maybe the problem is the way the starter button assembly is/isn't insulated?  or?  Like you, if I pull the black to green/red jumper I have off the solenoid, the short goes away but the starter doesn't work. What to do...

[alacrity]

And one last check before bed... Switch hanging loose from bars. All cleaned off inside.
Switch Is still grounded with green wire connected to starter button's brass contact plate.
Key off
DMM grounded and red lead connected to headlight white circuit in bucket (I disconnected my relays to test this now). It's straight from white switch out to headlight bulb connector white now, and that is where the red lead is.

With headlight selector in off position and DMM set to 200ohms, I have infinity. No resistance. No continuity.

With headlight selector in low beam position, I have 4 ohms.
(And if I press the starter button, it drops to 2.6 ohms!.)
If I move the selector to high beam, infinity again.

Now the blue:
Key OFF. Everything properly connected.
Red lead cionnected to blue high beam wire from switch and the blue wire to indicator bulb and blue lead to headlight plug.
Headlight selector off.  I show 4 ohms.  No change of I press the starter button
Headlight selector to low beam. 4 ohms again. No change if I press the starter button.
Headlight selector to high beam. 2.6 ohms. Drops to 2.2 ohms when I press the starter.

I think the twilight zone is where I am at ...