1986 K75C Headlights not coming on - K-Bikes.com - Excellence in Motion
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post #1 of 3 (permalink) Old Aug 23rd, 2010, 4:34 pm Thread Starter
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1986 K75C Headlights not coming on

Hey, I got my 1986 K75C earlier this summer and have been riding it problem free since. Yesterday I discovered that my headlights weren't on as I was riding around the city. Whether the switch for them is on or off, the engine is on or off, or just the ignition is on, they won't turn on. This is a K75C with the Sprint fairing, so there are two headlights. I did some tinkering around the bike and have found that the headlight relay (REC LD1A-12F) is clicking with the ignition and switch turning on-- but no lights. My thinking is that the previous owner had replaced the original bulbs with more powerful ones, and with this Tennessee heat... may have burned out. I've also checked the connections for corrosion and found some, but not enough to affect the operation and certainly not cause them to just not work. As far as I know they worked the day before because I rode home at dusk, but yesterday they could have been working at the beginning of my ride, but by the end they were not.

Any insight you guys might have would be awesome.


EDIT: Refitted the original lights, no change. Seems there's no power getting to the headlight unit at all. Thought about opening up the High/Low beam switch case to see if the connections had melted as they sometimes do, but the screw is really stuck in there and I'd rather not risk stripping it out if there's another option.

EDIT: It's getting 12volts at the relays (both the same model, REC LD1A-12F), but nothing at the bulb connectors. 12volts at one relay when the lights are in low beam, and 12 at the other in high beam-- but nothing at the bulbs for either setting. Not quite sure my schematic skills are up to par to draw this out, but I can try if anyone thinks it may help.

Last edited by pallum; Aug 23rd, 2010 at 8:48 pm. Reason: New info
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post #2 of 3 (permalink) Old Aug 24th, 2010, 8:02 am
Join Date: Mar 2009
Location: Clifton Beach, Tasmania, Australia
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Basically without knowing the specific wiring it sounds like the hi/lo beam switch is working as the 12V is switching between relays.

The fact that you have relays will have taken the load off the handlebar switch and reducing the likelihood of failure.

What you may be missing is the main high current 12V feed which may come from an inline fuse for example. On mine with the Eastern Beaver kit there is just a lead direct from the battery through a fuse.

Phil Mars

1984 K100RT
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post #3 of 3 (permalink) Old Aug 25th, 2010, 3:40 pm Thread Starter
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The in-line fuse was fine, but it's holder assembly was fried. I suppose why I was still getting 12volts at the relays is because it was coming from the hi-low switch, but not coming to the headlights because the hot line from the battery only goes through the relays, not the switch.
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