Topic: Hi Beam Headlight Fuse Blow

[heymak]

Hi Guys Just been out for a late night ride for about an hour , the last 30 mins I was really licking on with the high beam on for most of the time , never had this problem before on low beam mostly ,
About 1 mile from home I switched the lights to low beam and all then lights went out , got lucky cos iff it had happened 5 mins earlier I could of been in some real trouble out on the moors its quite bendy roads ,
Anyway got home and a blown fuse was the culprit , any guesses on what it could be the cause ?
Cheers

[Vinhead1957]

Check the fuse connections make sure they are very clean. Another culprit is corrosion in the headlight connections in the bucket.

[calj737]

Any chance you've changed the headlight to a much higher wattage unit consuming too much current? Glass fuse? If so, did it blow at the end or in the middle. This indicates the likely cause (short vs current)

[heymak]

Hi , Yes I changed the headlight I think its a H4 halogen , will a lower wattage H4 help ?

[calj737]

Perhaps. What is the wattage you changed to?

[RevDoc]

Any chance you've changed the headlight to a much higher wattage unit consuming too much current? Glass fuse? If so, did it blow at the end or in the middle. This indicates the likely cause (short vs current)

Calj, I've never heard of this re glass fuse links. Would you please clarify the specifics?

[calj737]

Insight from TT: There is a difference between the fuse blow form over current and the fuse blowing from external heating.  The former blows near the center of the link and the latter parts near or under the end caps.

Shorts and grounds usually cause the over current issues.

Oxidation and/or wrong length fuses usually cause the external heating issues.