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Headlight low-beam won't work :(

Discussion in 'Technical and Troubleshooting Torque' started by Iondah, May 11, 2007.

  1. I discovered last night that my bike (1988 Yamaha SRX250) has developed a strange problem: The headlight doesn't work when switched On, and in low beam. The dash lights up and the tail light goes on, but nothing shows up front. When I switch to high-beam the light comes on and everything is normal.

    The way the switch blocks are set up on this bike is with a light switch on the right switch block with "ON, PO, OFF" settings, and a "HIGH, LOW" setting on the left block. I've had a fiddle with all the controls and I'm sure I'm not just pushing the wrong button.

    Any suggestions on what might be wrong and how to fix it?

  2. From your post are you suggesting that when you switch it back from high beam to low beam that it then works and not vice versa?

    a few things come to mind from experience with my 1st bike...
    (1) check the fuse 1st. Some bikes had low beam wired to a fuse marked headlight AND ran "high beam" off of the main fuse (this was done for reasons relating to the passing switch - I don't really understand why). Don't assume that just because high beam works that the fuse isn't gone (I made that mistake)

    (2) Check the light globe since it is likely a dual filament. Low beam gets the most use and the filament gets distorted and worn the most - causing it to blow.

    (3) Corroded wiring. Low beam is used the most, wires/connections in the switch get the hottest and most degraded due to poor contacts in switches. Sometimes it is the on/off switch itself, or in my case, the wiring behind the ignition key including the contacts in the ignition switch can all become corroded/oxidized and loose. Usually related to age and weather.

    hope that helps
  3. Thanks Doug, that's given me a few things to try.

    Just to clarify....

    When I have the healight switch set to "ON" and the high/low switch set to "Low" the headlight is not on, although the bike does give all the other signs of the headlight being on such as the desh lighting up.

    When I have the headlight switch set to "ON" and the high/low switch set to "High" the headlight comes on with high-beam and everything is normal.

    No amount of flicking switches or changing the order can make the low-beam come on.
  4. Your low beam filament is blown.

    Change your globe
  5. Ok, that sounds like the problem then. Where do I get a globe and how do I know which one to get?
  6. any servo will sell them, so will kmart, supacheap auto, and I've even seen them at the supermarket.
    take out your old globe, check what sort it is..... probably a H4.
    new globe should be about $10
  7. Remove globe
    Take to servo/kmart/auto shop
    find one the same
    When installing the new one do not touch the glass with your fingers but handle it from the metal plate or wear thin cotton gloves.
    Skin oils kill quartz halogen globes prematurely
  8. its an 1988 bike. Chance that it is a sealed beam?
  9. I don't think so... it has a rectangular headlight and the globe is a small tube which goes across the middle of the casing.

    I think the globe is kind of like this:

    (Original pic was nothing like the real globe)
  10. lolz, its a tube light.

  11. well...I'm lost. Both the tubes you picture above are 240v halogens. I very much doubt someone went to the extent of building a mini 12-240V inverter to run such a light on your bike.

    have you a real pic of the headlight and globe?
    without a pic, it is too hard to say.

    If it has been modified from original, maybe you should start from scratch, go to the wreckers and get the real thing.
  12. Sorry for the wild goose-chase everyone. Just didnt get around to taking a proper pic of the light. I'll do that today.

    In the mean time, the headlight looks like this:


    But with fairing on the front like this:

    I had a closer look at the headlight, and I think it could be a sealed unit as I couldn't find a way of getting the globe out (pulled something out of the back of it but it was just the power cable) of the reflector unit. It also looks like I won't be able to do anything without taking the whole front fairing off as there is very limited access to the back of the light. :(

    On further investigation I discovered this: http://www.eautoworks.com/html/bulbSearch-1-YAMAHA-SRX250.htm

    Which seems to confirm that I need an H4.

    Now to get it in... would someone be able to help me do this? I'm in Glen Waverley (VIC) but happy to travel in Melbourne if someone is willing to help me out. [-o<
  13. :grin: It's fixed. I got a bit violent on it this time in terms of pulling things apart and discovered that there was just a black rubber seal over the end of the globe preventing me from getting it out. Once that was gone it was a bit fiddly but easy enough. So I have light! :grin:

    Still, the poking around behind the dials did make me realise just how screwed up the wiring on my bike is.

    So the next thing... what are "Pass" and "PO" for and why don't they work? :grin:

    I should add: Vic was correct - the low beam bit of the dual filament blew and the correct globe size was H4. Thanks everyone! :)
  14. When the pass push button switch is depressed, it should light both low and high beam together. PO I think is parking only lights (ie, there should also be a 3-6W globe in the headlight) which should come on - including the rear parking light.

    The CB I had was hopeless for all this - I pulled off the controls from the steering bar, and all the contacts were oxidised/dirty. You can clean them up with a bit of steel wool and protect them with WD40 (or something). Putting it all back together an in the position you like can be a real biatch tho.
  15. Thanks Doug.

    So how do I get to the 3-6 watt globe? That's probably blown too then.

    Pass definately doesn't work, no light when I press that.

    When I said the wiring is bad.... the bike has had a head-on at some point and has been repaired, badly. Most of the wires have been re-joined with crimp clips not even soldered :oops:
  16. If that is the case, then I would get a friend to help you start from scratch - using relays, solder, heatsrhink and stuff. On my 1st bike (the C8) before I did anything to it, stuff kept failing - 1 thing after the next. One night, probably 500m from home, the headlight went out and I couldn't fix it on the spot - the contacts behind the ignition switch had passed out :(

    Things can get messy when stuff like that starts to happen. I would honestly start reconnecting wires properly, 1 by 1 and seal them from the weather if you ride it in the rain.

    As for the front parking light, if you have one, it usually sits in a separate rubber grommet just below the H4 globe you replaced. Not all bikes have a front parking light, but if you have a PO switch, the assumption is that you will (even if it is missing).
  17. Thanks... yeah the bike does have the PO globe, its sort of in the side of the headlight mount though... not sure how easy it will be to get to.

    As for the wiring, haven't had too many problems so far, apart from my horn dying one day. Fixing it up is something I've been meaning to do, unfortunately it's going to be a massive job. I'd basically need to take the whole front of the bike apart to get to the wiring :(

    Any ideas on the "pass" thing? Don't really feel like pulling the switchblock apart...
  18. I don't know without looking at it Iondah. Mine didn't work until I pulled the switch block apart and cleaned it out. You might just have a loose wire as you suggested. If you don't want to pull it apart, I wouldn't worry - I've never used my passing light, and doubt you have either considering it doesn't work. Most people ignore or don't see you flashing it anyway.