|Posted on Sunday, April 10, 2011 - 06:52 pm: ||
2005 XB9SX, dual headlight mod (to fire both with high beams on).
It started doing this over the winter, and has gotten worse lately.
Symptoms: When I start it, the low beam stays off for a bit and then comes on (sometimes dim for a fraction of a second then full brightness). The high beam works fine when the low beam is off.
I initially thought, over the winter, that this was a low voltage cutout issue, and it was killing the low beam because the battery was cold, the oil was cold, and had pulled a ton of amps cranking.
It's doing it now that it's warm out. The bulb sometimes is dim right when it comes on, and responds to engine RPM, but after the bike has been running a bit, everything remains full brightness.
So, I have two theories up for debate:
- Either there's a relay (a headlight relay, or the headlight cut-on-start relay) acting up, or
- I have a charging system issue and there's a low voltage cut on the lights.
The bike hasn't shown any signs of a charging system issue, though. It cranks fine, lights right up, and generally behaves just fine. I don't throw it on a battery tender or anything else that would mask a charging issue.
Is there a relay that's likely to be at fault?
|Posted on Sunday, April 10, 2011 - 07:02 pm: ||
The headlight circuit (high and low) have a cutoff that will kill the lights when you are pressing the starter. If you did the highbeam on mod, you probably are running the high off the aux or accessory line, which isn't tied into that same cutoff.
I've never seen a bike act up with the lights the way yours has, so I couldn't say for sure what is going on, but it does sound like a relay. I would swap the relays around on your bike and see if the problem goes away.
|Posted on Sunday, April 10, 2011 - 07:13 pm: ||
The high beam is running off the stock high beam line - my flash to pass works properly. I put the low beams on the aux line, which is probably tied to the starter cutoff relay.
Do you know where that particular relay lives?
|Posted on Sunday, April 10, 2011 - 07:42 pm: ||
Err, yes you are right, the low would be on the other line, so the aux line would be the one having the issue, and it isn't on any relays as far as I can remember for your bike.
Still, the relays are under the seat next to the fuse box.
|Posted on Monday, April 11, 2011 - 11:31 pm: ||
The low beam totally cut out tonight and didn't come back. I *like* when problems become constant. They're much easier to troubleshoot.
I went through with a voltmeter, making sure I had voltage to the ACC fuse, and to the front connection behind the flyscreen. Everything looked good... except a visual inspection of the connection.
It looks like the low beam connection was loose - the female connector wasn't as tight as the others (make obscene jokes here), and there was evidence of excessive heat - some minor melting of the plastic.
I tightened the connector down with a nail, put everything back together, and so far it's working. I'll see how it is the next few rides, but a high resistance connection going intermittent open would explain the symptoms.
I probably loosened this a bit when I was working on swapping things around to do the dual headlight mod. I'll report back if this doesn't turn out to be the complete fix.