Topic: Ignition switch failure?

[Robby368]

Hello folks, I have an odd issue at hand.  I'm working on getting my K3 street ready, it's been on the center stand for months. I have cranked it up several times during the process of working on the carbs etc. It has ALWAYS been on a battery tender, new battery also. 

NOW all of a sudden, there is response from the ignition switch. I turn they key on and no headlight, brake light, cluster lights, no spark.

I checked the continuity and it appears to me that the ignition switch (new aftermarket) is working correctly. How can I verify?

And if the switch is good like I think it is, where do I begin? What else could cause total electrical failure?

[bjbuchanan]

Check main fuse using ohms scale on multimeter, not the eye. If it is 'good', replace it with another one. Then see what happens.

Lots of on/off, charging battery can easily blow the main fuse, only takes a little mishandling to spark something real quick. It doesn't take much

Another check if that is fine is too check voltage at red before keyswitch and then at the BLACK that comes out, close as possible to switch. Hopefully reads near 12V.

Brown should also show 12v for a stock setup, checking either before the fuse should show same/similar results.

New switches are so-so. I doubt you have melted it from test and tune but guys have melted the cheapie EMGO switches from riding around with them. Check voltage drop across the switch also. Anything greater than a couple tenths is no good. Stock OEM honda drops about .2 volts when new, use that as reference. Little more is okay, .7 clearly not

[PeWe]

The problem here seems to be a blown 15A fuse, or the fuse placed where it should be a 15A fuse, main fuse.

I bought a cheap aftermarket switch to my 2012-2014 restoration (The last years using the bike during the 80's I had a hidden switch under the tank when the OEM switch stopped working). I installed relays after reading here about the bad after market switches.
http://forums.sohc4.net/index.php?topic=70784.msg786405#msg786405

Now 4 relays: 2 for Headlight Hi/Lo (hidden inside my headlight bucket, newer car relays are smaller nowadays), 1 for ignition (placed beside the fuse box inside left side cover) and 1 for horn (placed beside horn). (My cheap China dual snail horns do not work properly without relay with 15 gauge wire from battery, not enough current via the crappy horn switch)
Easy to connect, the wires feeding the bulb, coils and horn switch now to the relays instead. Thicker wires direct from battery (connected on starter solenoid in connection) with a hanging fuse close to the battery to the relay and from relay to where the wire went now switching on the relay.

I do not trust the crappy handle bar switches either, wires soldered direct into a small copper spot, nothing physical holding the strands in the connection.
Strange that I did not use relays back in the days when I replaced all wires, solder them to all bad connections. I have worked with electrical and electronic stuff all the time and had access to all parts needed except for the cheap 12V car relays often used for extra stuff as strong lamps, horn.

My new switch however, have all wires of similar thickness. I have red somewhere here on this forum about cheap aftermarket switches that have thinner wires. My from CMSNL are all looking OK, part no. 35100341700P.

[Deltarider]

not enough current via the crappy horn switch

On the other side, if it had that current, that switch wouldn't live long.
BTW, is that a switch in the picture?

[bjbuchanan]

He's showing the same size wires coming off the ignition switch to the switch block. Compared to OEM the difference is real obvious with the red and black

[PeWe]

Yes, wires to the switch connector. The switch itself is at the other side of the black hose covering the wires.
 I read about thinner wires used in after market switches.
I have no OEM to compare with. OEM switches on Internet are all covered with tape all the way and around the connector.
- Anyone that has a photo of a Honda OEM switch with wires visible?

[bjbuchanan]

I don't have my switch on hand to take pictures but I compared it old vs new and it was a clear difference in the size of the red in and black out. The guage of the wiring was not the same, I didn't just eyeball the insulation and call it a day. Another thing is that it is the contacts inside that are insufficient

[Spanner 1]

Just another case of a 30 something fuseholder not passing the required amperage to work. the 3 fuseholders must be shiny clean and also grip each fuse tightly ( you should not be able to pull the fuse out with your fingers ) or no 'turn on' when you click the key to 'on'...... also check the battery connections for shiny and tight.... 'shiny' is the main focus for solid electrical connection, anything less = trouble now or then