Testing a bad connection

Red Fthr

Red Fthr

"Man is born free, and he is everywhere in chains"
1971 Honda CB500 F k1

I'm probably not using the right terminology by saying "testing a bad connection". I'm trying to track down an electrical issue I'm having by using a multimeter. I simplified my wiring harness and ever since, my starter and killswitch controls have stopped working. I don't really know where to begin.

Can someone point me in the right direction as to what and how to test my wiring to sort out this problem?
 
you want to check to see if the switches are getting power and if they are on a complete circuit... so

Unplug the switch connections..
On your MM you need to select the range that's correct - probably 20 on the DC side (0-20). Some meter auto tune.
Now you can touch the wires on the harness that you had connected to the switch and see what voltage you are getting..if it doesn't read then you know there's a short somewhere in that harness... if it reads ok, then plug the positive back into the switch lead and touch the MM positive to the switch negative cable while MM nagative to harness negative..... if it reads then play with your switch and check it actually functioning as a switch.. if it doesn't read then you have a bad switch or wires to it.. rinse and repeat...
 
I disconnected everything from the wiring harness to check the harness as instructed everything read around 10.87.

Being that the black/white wire (emergency kill) is a male end. I put the + of MM into the + of the harness and then touched the negative to the black/white wire and got a reading around 10.87 aka the opposite of the female pieces (- of mm into - of harness). Is that correct so far?

I don't think my switch has a negative lead. I don't see a green wire, which is the negative to my understanding. I have white and blue (high/low), 2 blacks (12v/postive), black/white (emergency kill), yellow/red (start), and brow/white (instrument lights).

Maybe I have the descriptions wrong.
 
Yeah, i kinda used the wrong terminology, when I think of testing I think of things in mini ccts, but there's really not a negative per-se coming form the switch...it's black and black/white to the kill switch so if you were testing that you'd plug one of the wires into the harness and complete the cct with the MM...

Not sure if you have a wiring diagram but it sure help... check out http://www.oregonmotorcycleparts.com/Diagrams/CB500.pdf -- think this is right for your bike but double check..

It could be the kill switch cct is the only thing that's not working cos the starter isn't going to work without that working first.
 
The black/white wire should not have power if it's disconnected from the kill switch. The black/white gets power from the black wire that feeds into the kill switch, but only if the kill switch is set to 'run'.

If the black/white wire has power with the kill switch disconnected, check down near your coils and ensure there are no black wires plugged in down there.
 
Ok, So I've tested the switch itself and here's what I've found:

With the 2 black 12v wires from my switch plugged into my 12v wire wiring harness connector, I used the + lead on my MM to get the following readings:

Kill-11.0
Starter- 4.4
High-9.3
Low-7.1


I would assume my next step is to take apart my switch and see what's going on with that starter wire?
 
The kill is the only one that looks close to right. It's still low, but the others are even more so.

What kind of voltage are you getting from the black wires leading into the switches?
 
Sonreir,

I just read your responses. Let me retrace my steps and get back to you. In the garage now.
 
I realized I did some things wrong the first time so I went through the process again the right way. With my MM set to 20 DCV the negative lead tapped into the ground (green) of my wiring harness, I retested everything.


The battery itself is only at 9.62V and dropping (I keep forgetting to turn it off and left it on for awhile last night)

Harness Results:
Black (12v) = 9.42
Black/white (kill) = 0
yellow/red (start = 9.32

With the black wires from my switch connected to my wiring harness and negative lead of MM still connected to the ground in my harness I found the following switch results:

Blue (High) = 9.17
White (Low) = 9.21
black/white (kill) = 9.23
yellow/red (start) = 0.03

If I've done everything correctly, I think it's safe to assume my starter wire in my switch might be hanging on by a thread and need to solder it back?
 
All those readings look right considering your battery is way past the dead mark (anything under 11.5V is a dead battery).

The starter button usually grounds the solenoid to activate the starter motor, so voltage when it's disconnected is correct. One other test to try is to measure resistance on the starter button. Disconnect the yellow/red wire from the solenoid and measure between that side of the wire and the negative terminal of the battery. You should get no reading. Try again, but with the starter button pressed and you should get under one Ohm.
 
Just got back from lunch and tested the resistance as instructed. And using the setting that makes a beep on my MM I got the following results:

Without use of button = -1
With use of button = -1
 
OK... one more check... Your solenoid: Aside from the yellow/red wire, what color is the other (thin) wire going into it?
 
I'll pull it apart and see what's going on.

Thank you for all the help guys. I've learned a lot through this process.
 
I'm gonna go ahead and assume I found the issue. lol
 

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soldered it back together and it's still no good. I then touched the open wire to the bike and got a faint start from the starting motor.
 
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