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Would a bad headlight relay cause headlight to sometimes turn on/off at random?

Discussion in 'Technical and Troubleshooting Torque' started by grue, Jun 20, 2010.

  1. EDIT: cjvfr is the winner! :rofl:

    However, in case someone in the future runs into the same issue, I'll leave my post:

    I've had an intermittent problem for about 2 months that I keep forgetting to deal with because it only comes up about once a week… sometimes when I turn on the bike, the headlight turns on, as usual. Then I'll press the starter and the headlight goes out, but the bike starts fine. At this point, pulling the trigger to flash the high beams works, but the rocker switch to turn the high beam on constantly won't work.

    Usually I can just turn the bike off, wait a second and start it again and it'll be fine, but I'm scared it'll go out and stay out one of these times. My version of logic dictates it'd pretty much ahve to be the relay (the bulbs and fuse are clearly fine, there's no problem with power flow, etc), but I figured I'd check with you guys before I dick around changing it if someone's heard of this before and knows that's not hte issue.

    Bike in question is a 2001 CBR600F4i
  2. relay possibly, switch maybe. Easiest option is to replace the relay, and see if it fixes it, if not well onwards and upwards.
  3. Yeah, I'm really hoping it's not the switch, that'd be annoying as hell. Then again, the switch doesn't have a setting to turn off the main beam, just the high, so it's pretty unlikely in my mind, at least until I get out the service manual and look at the wiring diagram.
  4. Looking at the wiring diagram for it the Start button has a set of contacts that open the headlight relay while the engine is cranking Grue, so it is possible that it is the start switch. Dirty contacts perhaps? But I agree the relay is probably the quickest easiest possibility.

    Service Manual: http://www.freeebookpdf.net/motorcycle/honda-motorcycle/honda-cbr-600-f4i-service-manual/

    Actually after a second look the relay only effects the high beam, the low beam is directly off the start switch so it is looking more like the start switch sorry :( Some WD40 sprayed into the start button may do it.
  5. EDIT: 100% correct. I just went out, activated the kill switch, and then turned on the bike and hit the start button a few times. Sure enough, one of 'em the light didn't come back on. Smacked the bottom of the switch housing and it popped right on.

    Oddly, the service manual doesn't seem to get into disassembly of the right switch housing. That's… interesting. I'll fire some WD in there I guess per your suggestion, but I'm gonna eventually crack it open and clean it out.
  6. One possibility is that switches are generally designed with contact wiping as part of their operation, i.e. the contacts mechanically move across one another to clear any buildup. You may me able to disconnect the battery and just press the start button a number of times to clean up any crud. May work and easier than dis-assembly. :) Good luck.
  7. I'll give that a shot, thanks for the help on this. I hadn't considered the start button and I might have never figured that out.

  8. do you ride in the rain?
    i have done so in the past and it makes some of my electrics on my f4i a little dodgy untill it drys..
    like above remove and dissasemble switch if possible and clean..