Headlight failure - left combo switch or other cause?

[Motorhobo]

UPDATE: A while ago riding with my 945 K75's OEM heated grips on, I caught a whiff of melting plastic and realized my low-beam headlight was out. So I did a little search and found this old thread:
UPDATE 2: This doesn't appear to be related to the left combo switch at all. Read on...
UPDATE 3: Unless you need a new combo switch or your headlight socket has broken, skip to bottom for resolution.

https://www.motobrick.com/index.php?topic=1389.0

Based on that, I just pulled the headlight, replaced it with one I had lying around and same result: low-beams don't work, hi-beams work, flash-to-pass on the switch works. Blue indicator on dash doesn't work when hi-beams are on. No apparent melting of any wiring under the tank or in the E-box. The headlight tabs came out of the (original, not ceramic) plug no problem, no sign of any melting. I have the Eastern Beaver relay installed with Posi-Locks, and that looks fine too. So according to this thread, the most likely culprit is the left combo switch, and I have a spare of that, so this could be an relatively painless fix.

Having said that, am I wrong that this really shouldn't have happened with the EB relay kit? Isn't current through switch with the relay insufficient to melt those contacts?

So before I replace the switch I'd like to rule out other possible causes if this and ask if the heated grips might have played a role. I know you're not supposed to run the heated grips on the higher setting for any length of time, but not being sure anymore which is high and which is low on that switch it's not unlikely it was on high.

Here are the questions:  1) Is there any other way of testing the left combo switch short of replacing it and 2) can OEM heated grips have been the factor that fried the switch?

Thanks for any help...

Van

[Scott_]

Yea, if you have the EB relay kit installed you shouldn't have had any NEW damage from lamp current. That's not to say it wasn't previously damaged prior to you installing the relay kit.
It's also possible that the contacts are just plain dirty.
As an electrician by trade I have seen some switches stop working because there was not enough current being switched on/off to keep the contact clean.
You may be able to disassemble the switch to clean and grease and correct your issue without replacement.
Just be careful with the springs, they like to be free.....

[Motorhobo]

OK, thanks Scott. I'll replace the switch with the one I have from a prior teardown and when I have several hours to be frustrated, I'll tear apart that old switch and see if it can be rehabbed.

If swapping out the combo switch doesn't do it, I'll check back in.

I'll just assume there's no connection between the heated grips and the switch failure...I don't see how that would be possible since AFAIK those things are on different circuits but never say never with these ancient K-bikes.

[frankenduck]

Left combo switch:
https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/leftcombosw/leftcombosw.htm

[Motorhobo]

Thanks, Duck - you da man! I remember doing this once before for my first K75 which I parted out back in '16. The switch on the K75 in question is the original '94 switch so I guess its time has come.

[Motorhobo]

I finally got around to replacing the combo switch but though I could've sworn the spare switch I replaced the bad one with was working when I installed it, apparently it does not work now or there's some other reason the main headlight doesn't come on. Before I do anything else I need to make sure power is getting to and coming out from the combo switch connector under the tank. Can anyone please remind me what the wire colors are going into this plug, or better yet, which connection in the plug does what and what the amperage is supposed to be? I'm looking for the main headlight wire. Brights and running light work fine.

Any other possible reasons why the main headlight wouldn't work would also be appreciated. I have the EB relay kit installed.

Thanks...

[frankenduck]

WHT/YEL is headlight power in from right combo switch

WHT is high beam out
YEL is low beam out

[Motorhobo]

OK, thanks Duck. I have power on YEL going to the headlight connector. YEL connection at the connector tests OK, as does the female connector that the headlight tab plugs into. So either I have two headlights with dead low-beams or a connector that defies the laws of physics, or I'm missing something.

But all that is secondary now, because the ancient connector broke while I was holding it between my fingers. The outside piece holding the female connector for the brown wire broke off and now the for the brown wire isn't attached to the connector body. I guess I could the connect headlight tab manually to that female connector and shrinkwrap it but, I'll wait to hear what other people say about that.

I have a spare harness from a parts bike I could scavenge the headlight connector from. So my questions now are:

1) Can I get an aftermarket connector or should I recycle the other ancient one from the spare harness?
2) Can I get any connector in there without a whole lot of in situ splicing/soldering? The YEL wire goes to the EB relay - can't I tap in there?
3) Should I use this opportunity to put a connector in for a different, better headlight that will work with the stock wiring and EB relays?
4) What would frankenduck do?

I should mention I have what looks like a 9004 headlight and probably also the connector for it somewhere that I inherited from Gary Weaver when I bought his '94 K75. I'm not sure where he had that running - he had lights all over the bike but I removed them because I had no idea how it was all wired. It's possible that was what he was running as the main headlight, but I can't remember - it was ten years ago. Does anyone have experience with 9004's on a K-bike?

Thanks for any help...

[frankenduck]

Just to confuse you even more, a few years ago I came up with a better headlight relay setup for K bikes. Why is it better? Because even if your hi/lo switch goes completely tits up dead you will still at least have a low beam:
https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/hl.relays/hl.relays.htm

[Scott_]

I've had my headlamp socket crumble and fail as well. I just went to the local autoparts store and purchased a generic H-4 headlamp pigtail socket and spliced it into the harness. I debated on ceramic or not and decided not, as I also use EB relays now so I didn't anticipate there being enough current/heat passing thru this specific connector to need the higher temperature rating.

[Motorhobo]

Thanks frankenduck and Scott! Duck, I don't know where you source your stuff, but it looks like it's hard to find a ceramic socket without pigtails and most of them are 16AWG. Sadly Amazon has been dominating the hits for pretty much anything, even though it's little more than a garbage peddler these days. Using -site:*.amazon.com on DuckDuckGo works sometimes, sometimes not. Auto parts stores sell the same garbage it seems, and charge 6X as much. Anyway, I have one that hopefully isn't crap on the way and will let you know whether I get some low-beam love after that.

Thanks again...
Van

[frankenduck]

I use ceramic H4 sockets that come with terminals so you can pick your wire gauge.



https://www.kbikeparts.com/otherstuff.htm

[Ingo]

Got the same from Amazon, only the plastic part is yellow....

[Ingo]

... I debated on ceramic or not and decided not, as I also use EB relays now so I didn't anticipate there being enough current/heat passing thru this specific connector to need the higher temperature rating.

Wrong, the bulb connection has the same load with or without the relays, unless you go with lower wattage bulb.... (Actually even slightly more since less voltage drop)

[frankenduck]

Wrong, the bulb connection has the same load with or without the relays, unless you go with lower wattage bulb.... (Actually even slightly more since less voltage drop)

Ditto what Ingo said. The advantage of HL relays for Ks is that they put less current through the switch contacts, not to the bulb.

Even if you're not heating a plastic socket to the point where it melts, it still heats up a little so that repeated heating cycles, along with age, will degrade the plastic over tine. That's not an issue with ceramics since they can endure heat cycling and aging much better.

I use LED headlights that are only 25W for either beam but still use ceramic sockets because I have them on hand and it doesn't hurt.

[The Mighty Gryphon]

Wrong, the bulb connection has the same load with or without the relays, unless you go with lower wattage bulb.... (Actually even slightly more since less voltage drop)

I'm not positive what you're trying to say, but a lower wattage bulb will draw less current through the connector so the I squared loss through the resistance of the connector will be less.  Also, the bulk of the heat in the connector is conductive from the bulb's filament through the wires connecting the filament to the connector. 

A higher wattage bulb generates more heat than a lower wattage bulb, and the higher wattage bulb sends more of that heat to the connector.

For example: A 60 watt bulb will draw about 5 amps while a lower wattage 50 watt bulb will draw about 4 amps.  If we assume the connector to have a resistance of 0.1 ohms the energy dissipated in the connector's resistance is 2.5 watts for the 60 watt bulb and 1.6 watts for the 50 watt bulb.  Meanwhile, a couple inches away there is a wire filament being heated to somewhere around 3,000 degrees C.  The higher the wattage of the bulb, the higher the temperature is.

[Ingo]

I was talking about the current load in the plug, which is the same regardless of relay or not. With relays there is likely more a bit more current due to less voltage drop along the supplying wiring. Unless using lower wattage bulb. I have the same setup, with old Bosch relays from my saved parts and LED headlight bulb, not sure of wattage right now, but certainly less than 50/65.

[Scott_]

Ditto what Ingo said. The advantage of HL relays for Ks is that they put less current through the switch contacts, not to the bulb.

Even if you're not heating a plastic socket to the point where it melts, it still heats up a little so that repeated heating cycles, along with age, will degrade the plastic over tine. That's not an issue with ceramics since they can endure heat cycling and aging much better.

I use LED headlights that are only 25W for either beam but still use ceramic sockets because I have them on hand and it doesn't hurt.

I should clarify which H4 socket I replaced.... I replaced the stock/factory plug-hence the one that feeds 'control' signal power from the bar switch to the EB relay setup. The headlamp then connects to the H4 socket pigtail supplied in with EB relay kit for the actual lamp power...


So then the socket I replaced does not pass headlamp high power/current, only the low power relay coil current.


This is the kit I'm using.

[The Mighty Gryphon]

None of that invalidates anything I wrote.

[Motorhobo]

I should have known somehow there'd be a controversy!

I'm no expert by any means but if I may use an analogy -- even if you pee on a tree, it's the big hairy turd that's going to clog up the toilet. Similarly, even if the switch's control circuit goes elsewhere, it's the big hairy current needed to power the bulb that will pass through the connector. So maybe a ceramic connector might be better, but I agree with Scott that really doesn't matter. I personally think those original OEM connectors melt because they were cheap to start with and suffer corrosion and deterioration from age. So it doesn't really matter too much what the material is, as long as it's new, fresh, and better quality than the OEM. But please...the issue isn't worth the microbytes required to store endless haranguing about it in the database.

I looked far and wide for the connectors frankenduck showed in his pic. I think I found them here: https://www.hipoparts.com/. But I didn't think to look on kbikeparts.com. Next time I'll always check there first for anything.

What sucks is that Amazon basically owns the Internet now, so it's nearly impossible source things without scrolling past pages of hits to crappy Amazon garbage. Even if you use the exclusion operator:

-site:amazon.com h4 headlight socket

you might be out of luck because it doesn't always work on DuckDuckGo.

I ended up getting the connector from Amazon because I needed it quick, the wire is copper, and the pigtail is 14AWG. The headlight fits snug with no play. Would have been nice to have the correct color coding but can't have it all.

https://www.amazon.com/dp/B076JGTB7H?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

And after all of this, the problem was probably all due to the fact that both the headlight on the bike and my spare headlight were bad. But I guess we'll see...

Thanks guys!

[Laitch]

even if you pee on a tree, it's the big hairy turd that's going to clog up the toilet.
. . . low-beams don't work, hi-beams work, flash-to-pass on the switch works. Blue indicator on dash doesn't work when hi-beams are on.

The toilet problems disappear when you quit eating unskinned rodents.
The switch contacts could need cleaning and polishing—and even restoring—if they haven't sunk into their plastic base too far. Duck goes into this situation ad nauseam at his site with a dizzying array of photos. His instructions include a windshield switch component. I used the instructions attached below.
Maybe your new connector will solve everything.   

[Motorhobo]

UPDATE: A while ago riding with my 945 K75's OEM heated grips on, I caught a whiff of melting plastic and realized my low-beam headlight was out. So I did a little search and found this old thread:
UPDATE 2: This doesn't appear to be related to the left combo switch at all. Read on...
UPDATE 3: If your headlight socket broke or your combo switch failed, read on. Otherwise, throw out your headlight and any spare headlights you have lying around and buy a new one. Skip to bottom for resolution of this issue.

https://www.motobrick.com/index.php?topic=1389.0

Based on that, I just pulled the headlight, replaced it with one I had lying around and same result: low-beams don't work, hi-beams work, flash-to-pass on the switch works. Blue indicator on dash doesn't work when hi-beams are on. No apparent melting of any wiring under the tank or in the E-box. The headlight tabs came out of the (original, not ceramic) plug no problem, no sign of any melting. I have the Eastern Beaver relay installed with Posi-Locks, and that looks fine too. So according to this thread, the most likely culprit is the left combo switch, and I have a spare of that, so this could be an relatively painless fix.

Having said that, am I wrong that this really shouldn't have happened with the EB relay kit? Isn't current through switch with the relay insufficient to melt those contacts?

So before I replace the switch I'd like to rule out other possible causes if this and ask if the heated grips might have played a role. I know you're not supposed to run the heated grips on the higher setting for any length of time, but not being sure anymore which is high and which is low on that switch it's not unlikely it was on high.

Here are the questions:  1) Is there any other way of testing the left combo switch short of replacing it and 2) can OEM heated grips have been the factor that fried the switch?

Thanks for any help...

Van

[Motorhobo]

UPDATE: Both the installed headlight and my spare headlight were bad.
NUMBER OF HOURS WASTED ON THIS S**T: I can't count that high.
RECOMMENDATION: Be smarter than me. If your low-beam fails, throw it and any other 'spare' headlights you have lying around out and buy a new one.

[frankenduck]

UPDATE: Both the installed headlight and my spare headlight were bad.
NUMBER OF HOURS WASTED ON THIS S**T: I can't count that high.
RECOMMENDATION: Be smarter than me. If your low-beam fails, throw it and any other 'spare' headlights you have lying around out and buy a new one.

You could also put a voltmeter to the headlight socket.
BRN - Ground
WHT - High beam
YEL - Low beam

[Motorhobo]

Right...that was the question I asked in the third post in this thread :-)

Five years ago I probably would have been able to resolve this on my own. But back then I decided to ride the engine on this bike till it dies because I have another engine with a new top end waiting to be swapped in.

But the engine still hasn't died, the only thing I've done to this bike is lube the driveshaft splines, and in those five years I forgot everything I ever knew about motorcycle maintenance and repair.

Use it or lose it.