Honda CB650C Lighting Problem

Message

OldBlue · #1 Unread post by **OldBlue** » Mon Aug 07, 2006 11:31 pm

Hi. THe forum I used to use for my bike is gone, and I just found this one. So far, so good!!

My question - I noticed yesterday when I got on my bike that my headlight was out. Pulled it apart, and the H4 bulb is fine, but it won't work when I plug it into the harness. Everything else works fine, all the fuses are good. I was planning to tear into it tonight, but I was wondering if anybody had any ideas, other than a wiring issue.

Doug

Gummiente · Tue Aug 08, 2006 12:31 am

Did you just do a visual check of the bulb? The only way to be 100% certain is to use a multimeter on the "Ohm" setting or to try a new bulb.

OldBlue · #3 Unread post by **OldBlue** » Tue Aug 08, 2006 3:04 am

I actually hooked the bulb up to my extra battery, and both the high & low filaments worked fine.

Gummiente · #4 Unread post by **Gummiente** » Tue Aug 08, 2006 3:18 am

Ok, then chances are its a broken wire somewhere. Have you tried wiggling the headlight wirng harness while the light is on? Also, don't know if yours has it, but on some bikes there is a relay that cuts the headlight out when starting the bike. It's possible this realy is burnt, which means it won't let it light up at all.

OldBlue · #5 Unread post by **OldBlue** » Tue Aug 08, 2006 3:49 am

No, my headlight's normally on when cranking the engine. I was thinking a bad wire somewhere myself, and I'll track the wiring later today, since all the fuses are ok and everything was fine the day before. I just wasn't sure if this could be a common Honda problem, meaning maybe a bad switch or something else.

By the way, I checked out your page, and love the FXDI!

OldBlue · #6 Unread post by **OldBlue** » Tue Aug 08, 2006 11:21 pm

Gummiente wrote:Also, don't know if yours has it, but on some bikes there is a relay that cuts the headlight out when starting the bike.

It doesn't have a relay, but I did find the problem. When the starter button is released, it sends power to the dimmer switch, which in turn sends power to the proper (high or low beam) wire to the headlight. When the starter button is depressed, it breaks the circuit to the headlight. Well, after 25 years, the starter button had built up a bunch of dirt inside of it. I found the problem after tracing the wiring for about 2 hours. Cleaned the switch w/ contact cleaner, tested it, and put it back together. Works great again!

Gummiente · Wed Aug 09, 2006 12:51 am

OldBlue wrote:I found the problem after tracing the wiring for about 2 hours.

Well, there ya go. Those are the most rewarding and satisfying troubleshooting sessions, kudos to you!