Hi,

I'm adding headlight relays to my K100 as suggested but have a couple questions.

Online instructions say to use the yellow wire at the headlight socket terminal to trigger the low-beam relay and the white wire there to trigger the high-beam relay. But, my bike (1985 K100) has TWO dual white wires on the same headlight socket terminal. Why two wires there? And which one do I use to trigger the high-beam relay? Or should I use both of them?

Also, it seems like some of these wires at the headlight socket terminal are "hot" even with the key in the off position. That doesn't make sense, otherwise the headlight would be on when the key is turn off but it never was on. Here's what I found with a tester:

Dimmer Switch in Low Beam Position with Key ON
yellow wire (low beam?): 12 volts
white wire #1 (high beam?): 12 volts
white wire #2 (high beam?): zero volts

Dimmer Switch in High Beam Position with Key ON
yellow wire (low beam?): zero volts
white wire #1 (high beam?): 12 volts
white wire #2 (high beam?): 12 volts

Dimmer Switch in Low Beam Position with Key OFF
yellow wire (low beam?): 12 volts
white wire #1 (high beam?): 9 volts
white wire #2 (high beam?): zero volts

Dimmer Switch in High Beam Position with Key OFF
yellow wire (low beam?): zero volts
white wire #1 (high beam?): 9 volts
white wire #2 (high beam?): 12 volts

These readings don't make sense to me. If the headlight socket is powered even with the key in off position, shouldn't the headlight be on too? But it never was. Also, why the 9 volt readings? I checked everything twice and got the same readings.

The wire is all stock and worked okay last time I used the bike. If somebody could explain these things to me so I can properly install headlight relays, I'd greatly appreciate it.

Thanks!

The 2 white wires are for the high beam and the high beam indicator in the instrument pod (blue).
This is right, one of the white wire will go on the coil for the high beam relay and the yellow one will go on the coil for the low beam relay.
The other side of the coils should be grounded.
You pull a good size wire from the battery and put an online fuse (or better a breaker) to feed one side of the relays contact, and feed your headlight socket from the output of the relays
Check the light diagram here and you will understand.

Yes, I see the high beam indicator light wire (2nd white) downstream in the colored diagram. Mine join at the headlight terminal.

Should I hook up both white wires together at the relay (trigger) terminal so the high beam indicator light still functions? In other words, keep them together like they were. That sounds right.

I'm doing the rest like you said: heavier wirirng, fuse, etc.

Thank you!

The diagram is not always reflecting the physical wiring. This is the principle of the wiring.
For the wire that you select, It's up to you...
One or the other or both. They are in parallel and any solution should work.

The Eastern Beaver kit is the way to go I believe because there is no question what goes where and the sealed relays that are part of the kit are really excellent. If you get the ceramic lamp socket as well then uprated bulbs won't cook the socket.
Regards,
K-BIKE

Have to concur with K-BIKE re Eastern Beaver as it eliminates any hassles, it is too easy to fit and the workmanship is superb.

If you prefer you can get a kit that includes wiring for driving lights as well.

Not to mention all the other goodies on his site.

Regards,

Phil

Thanks Crazy Frog!

I didn't know about the Easter Beaver kit until now. And since I've already bought relays and other parts I'll continue with the home-brew method. I'll be adding small driving lights and extra rear lights next.