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I've recently come up against a problem where the RH headlight on my 2007 Honda Jazz does not work when dipped.

It is not a blown bulb, since the same bulb is used for full beam, which works.

I don't think it's a blown relay, since I can't find separate relays for R/L headlights, and the LH headlight is working perfectly.

I've had a look to see if I can spot any worn out wiring, but nothing that I can see with my (partially trained) eye...

Does anyone have any ideas of other potential causes/fixes for this problem?

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There are three possibilities:

1) a defective bulb, each bulb has two filaments so while the high may be fine the low may have failed

2) there is a blown fuse for the RH low beam - some cars have individual fuses left and right

3) the wiring to that bulb is damaged...

  • Ok, I'll replace the bulb as a first port of call, then? Fuses don't seem to be separate (will post a photo of the map when I go to swap bulb) – Jonathan R Swift Oct 24 '18 at 16:12
  • It was 1), thanks! Wasn't aware they had dual filaments, although it's obvious in hindsight! – Jonathan R Swift Oct 24 '18 at 19:59
  • @JonathanRSwift glad it was that, nice and easy... – Solar Mike Oct 24 '18 at 20:11
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Each headlight bulb has two filaments, one for dipped and another for full beam. You can see through the glass of the bulb to check if these have blown. If the plastic is too cloudy to see from the outside you will have to remove the bulb. enter image description here

  • Adding this with photo in case anyone else has the same problem, as I did search existing SE questions before asking. – Jonathan R Swift Oct 24 '18 at 20:02
  • Take care when fitting new bulbs, grease prints from fingers cause them to break.... – Solar Mike Oct 24 '18 at 20:13
  • I don't think I touched the glass... So the grease on the glass gets too hot, and causes the bulb to explode? Sounds dangerous... Should I remove it, give it a wipe with IPA and re-install to be safe? – Jonathan R Swift Oct 24 '18 at 20:21
  • Just habit for me to make sure not to touch the glass... differential expansion we were told... wasn’t an issue with incandescent, but halogen and now hid... – Solar Mike Oct 24 '18 at 20:30

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