Author Topic: Need some help trying to start bike with suspected frigged kill switch  (Read 20870 times)

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Offline b1jackson

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Yes. That will be on the list eventually. I had the box off and apart. No loose connections or solder, cleaned and polished with vinegar/salt then baking soda water mix.

Still baffling why I'd have 12v at the solenoid but no ignition

Offline b1jackson

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Ok, I appreciate the fact that solving a no ignition issue via forum posting is a tricky one so I am trying to be very systematic here with my steps.  Forgive if I write in an obvious step as this is a learn as I go process on a bike I've never heard run and have had for a couple of weeks only.

Testing process of key switch

- removed and unplugged the switch.  Wires feeding the switch in the harness are red, black, 2 brown wires and a brown/white wire.  The only wire receiving power was the red (12.3 volts)

- I plugged the key switch back in after cleaning the connections and adding some dialectic grease to the connections.  All snug and clean.  Turned key to the on position and the power was going to the black and red wires only (12.3 volts @ each).

- I then turned the key to the park position.  Tail light lit as it always has but no other lights.  I checked and had power to the two brown wires, the red wire, but not the brown/white one or the black.  (12.3 volts @ each).

Where should I go from here? 


Offline calj737

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Nowhere. That is exactly as the key should behave. Have you looked at the wiring diagram to understand which wires get "switched on" with what key position? Here's a sample for a 550 that is nearly identical for most SOHCs.

http://manuals.sohc4.net/cb500/service_manual/HSM500550_11.pdf
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Offline b1jackson

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Yeh, I'm going nowhere alright  :)

Good to know that I've eliminated the key switch as the culprit to no ignition.  I had looked at the wiring diagram but not such a clear one.  Looking at it and truly understanding it are two different things.

If I've got power as I've described in my recent post and power at the fuses, solenoid, etc would it be possible I have a bad ground? 

Offline b1jackson

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Here is an update to my misery and testing process in case anyone can help me narrow this down.

After my earlier confirmation that my switch was working correctly (thank you calj737), I wanted to test for power at the stater button.  Turned the key to on position, and no power to any of the right hand switch.  Cleaned it out with contact spray for electrical and will reassemble tomorrow. A couple of the wires feeding into the switch looked a bit pinched so I'll put some liquid electrical tape on the before I button things back up.

I'm at a loss and I think I've covered a lot of the obvious ground!  Help guys....I want to hear this beast running!

Offline scottly

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The black wire from the ignition switch connects 12V to the horn, the brake light, the nuetral and oil pressure lights, the voltage regulator, and via the kill switch, the coils. (The input to the kill is a solid black wire, and the output to the coils is a black wire with a white stripe) With the key on, test for 12V at the black regulator wire.
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Offline b1jackson

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Thanks for staying with me on this.  I'll check this later today and check back.

Offline b1jackson

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No voltage from the black wire feeding into the regulator >:(

My battery to frame ground is good and clean.  Where else should I check?.
« Last Edit: July 02, 2016, 06:04:29 PM by b1jackson »

Offline scottly

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That helps narrow it down to the key switch itself, or the connection of the black wire into the main harness, where all the other loads are fed from. You might want to check that the red supply wire still reads 12v with the key turned on. (A high resistance connection might allow enough current to light your LED taillight, but might allow the voltage to drop like a rock under the normal loads.)
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Offline calj737

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That helps narrow it down to the key switch itself, or the connection of the black wire into the main harness, where all the other loads are fed from. You might want to check that the red supply wire still reads 12v with the key turned on.
He got that step confirmed earlier...

Testing process of key switch
- I plugged the key switch back in after cleaning the connections and adding some dialectic grease to the connections.  All snug and clean.  Turned key to the on position and the power was going to the black and red wires only (12.3 volts @ each).

- I then turned the key to the park position.  Tail light lit as it always has but no other lights.  I checked and had power to the two brown wires, the red wire, but not the brown/white one or the black.  (12.3 volts @ each).

BJ - I think you need to start charing BLACK through the harness. Carefully open the headlight and locate the BLK connectors. With the RUN set to OFF, and perhaps a battery tender on, pull the headlight fuse (these steps save the drain on the battery) begin testing for voltage on BLACK with key ON. Sooner or later, you will find the disconnected/damaged culprit.
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Offline b1jackson

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Yes, will do.  I already have the headlight opened up.  The other possible factor in this since we are now digging into that is that it is not the original headlight.  A couple of the POs had swapped around different buckets so perhaps there is a mangled up black wire in there causing some grief. I hope so!

Thanks again lads for the prompts, tips and support!

Offline b1jackson

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Ok, here is where things stand now.  Followed Cal's suggestion and got into the headlight bucket. 

- repaired a white wire going into the headlight.  It was a bit ratty and the only one where I thought things looked rough.

- carefully and one by one, unplugged, cleaned with emery cloth, and put a dab of dielectric grease on every connection no matter the color.  The only wire disconnected is a brown/blue one that I am pretty sure is just the original tail light feed.  The male end was taped off.

- confirmed 12v at the ignition switch then started testing each connection having a black wire feed going in. 

The only one that registered any voltage was the single black into the black wire spade connector.  This look like it feeds into from the harness into the dash warning lights between the speedo and tach.  This one only registered 0.05 volts.

Again, key was in on position with a fully charged battery.


Offline scottly

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With the switch plugged into the harness, check for 12v on the black wire on the switch side of the plug, and also on the harness side of the plug.
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Offline b1jackson

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Ok.  Back from the shop with an update!

Stripped off all the tape in the harness up to the junction point of the black wires.  Things looked pretty good and I cleaned up one splice along the way.  Here is a pic of the junction point where black power feeds connect.  Tight and clean.



I then took a closer look at the fuse block with the volt meter (and not just the test light).  You recall it was a bit melted and I removed the lower brass clips as I had some power going into them and shouldn't.  I tested power (via the volt meter this time) and noticed the fuse blown.  I removed it and tested voltage to each end of the brass clip.  12.5v on one and 2.5v or something like that on the other? 

Then I thought I'd try and stick another fuse in a poof...burnt out in my finger tips.



Pretty sure both posts of the main fuse holder should read 12volts correct?  Is this the short causing me grief?

Yes...I will order a new fuse block as I think it's finally been solved.  Thoughts?

Offline scottly

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Was the ignition switch turned on when the new fuse blew? With no fuse installed, you should read 12v on one clip, and zero on the other. Please post a pic of the back side of the fuse block.
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Offline b1jackson

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Here is the back side of the fuse block with the bottom two clips removed.



I think the key was turned to "on" when I went to put in the fuse but can't confirm that.  It got a little hot in my finger tips!  Based on my further tests below though, it may have been off.

No fuse in holder, key in off position

0.12v on left side of main fuse terminal and 12.5v on the right side

No fuse in holder, key in on position

0.0v on the left side of the main fuse terminal and 12.5v on the right side


Here is a closer up of the front of the fuse block


« Last Edit: July 03, 2016, 05:09:53 PM by b1jackson »

Offline scottly

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With the key off, insert a new fuse. Does it get hot or blow? If not, turn the key to on and see if it blows or gets hot. (This assumes any loose black wires aren't grounding out)
Don't fix it if it ain't broke!
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Offline b1jackson

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 I'll pick up some more fuses tomorrow.  I hope we are closing in on it!

Offline scottly

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Well, I don't know if we are closing in on it or not yet. Not sure how you had 12v at the switch with a blown fuse? Don't worry, we'll figure it out. In the meantime, return all the wiring to the original configuration. (If you had asked, I would have told you not to bother to unwrap the harness. ;))
Don't fix it if it ain't broke!
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Offline b1jackson

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I'm ok with the re-wrap of the harness.  The bike is getting a slight cosmetic upgrade as well as I go along and new shiny tape looks better than old faded crusty stuff..  Plus I can get an idea if any butchery happened underneath by the PO.  Will check back in tomorrow.

Offline scottly

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Rather than buy new glass fuses, you might want to go ahead and switch out the whole fuse box? For testing purposes, you could get a single blade-fuse holder and wire it in place of the main fuse. The headlight and taillight won't work, but we're not concerned with them now.
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Offline b1jackson

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Do you mean just solder in a single blade holder in to the back of the panel onto the two red terminals?

Offline scottly

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No, unplug the fuse box from the harness, mount spade lugs on the new fuse holder wires, and plug them into the harness plug at the two red wire locations.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline b1jackson

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Key turned off, put in fuse....all good.

Turned key on and poof...out it went.

I bought a cheap inline fuse so will do the bypass trick next.


Offline b1jackson

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Insert sad trombone sound here......

Disconnected fuse block and plugged in an inline fuse (20amp) between the two reds and pop!

So where now?  Short somewhere between the headlight cluster and the fuse block?