Headlight problem.

[Bradders]

Morning.
Whilst riding home from work last night my dipped headlight stopped working, switched on to main beam, that didn’t work either! The only way I could get the headlight to work was the pass/ flash light switch.
Was wondering if anyone had come across this before or where I should look first.
Thanks in advance.
Chris.

[McCabe-Thiele (Ted)]

Morning.
Whilst riding home from work last night my dipped headlight stopped working, switched on to main beam, that didn’t work either! The only way I could get the headlight to work was the pass/ flash light switch.
Was wondering if anyone had come across this before or where I should look first.
Thanks in advance.
Chris.

Before blaming the switch I would check the earth side of the switch first - especially if the clock illumination went out as well.

[Bradders]

Thanks Ted.
I should of mentioned, all other lights including the clock illumination are working fine.

[Deano400]

Check the earth from the bulb (connector inside the headlamp) and fuse No. 2 (the middle one I think).

[taysidedragon]

Since the main beam is working on the headlight flasher I would suspect the light switch or it's connections. First place to look would be inside the headlight bowl and then the 'bag ' of connectors under the left side of the tank where the switch wires connect to the loom. If no luck by then it's probably a problem inside the switch itself.

[Deano400]

If I remember correctly the PASS works from the main fuse so can still work when HIGH and LOW are not. However that does suggest it's not the earth from the bulb.
The fuses from top to bottom are:
15A Spare
No 1 15A Main
No 2 7A Head light
No 3 7A Tail light
7A Spare
(Again from memory so check).

[Deano400]

Just had a look at the wiring diagram it's a Black/Red feed to the fuse and a Black/Yellow from the fuse to the switch. As Gareth says check in the headlamp and the bunch under the tank.

[Bradders]

Thanks for the replies guys. Will try and have a look in the next day or two. Just when the bike Is running well something else goes wrong. I guess that’s old bikes for you.

[Bryanj]

Fuse or fuse holder and or wiring to clips holding fuse is most common problem

[Bradders]

Thanks Bryanj, think I shall try fuse first, sounds the easiest to get at.

[Bryanj]

Dont just "look" what frequently happens is the contact at the clips gets weak and overheats which melts the solder holding the fuse element to the cap so it looks good but aint. The heat alst tends to melt the plasticbody of the fusebox which makes it worse.
A member on the US site makes direct replacement blade fuse replacements but you can do your own

[Bradders]

The fuse had blown so changed it with the spare. Headlight now works. Thanks very much for all of your advice. Am I right in thinking though that there must be a reason/ problem as to why it blew in the first place?

[Deano400]

It could be something or nothing.
It could be age related if it’s the original fuse. The original spec for the head light bulb was 50/35w. So that the head light doesn’t flick off during the transition from Low to High and High to Low both High and Low beams would be on for the short transition period. This would draw 7A during transition so I guess a 7A fuse over time would weaken and give up.
Any dirty / poor connection / earths would also increase the load and therefore the current.
I would check and clean the connections as there aren’t many.
Also check the rating of the bulb is as specified.
My brother had issues with his 400 and after stripping and cleaning the ignition switch connector everything was great.

[Bradders]

Thanks for the info Deano, I will buy some new fuses from Silvers and try that first I think.

[TrickyMicky]

As stated by others, we tend to sometimes forget the actual age of our steeds. When I had a fuse problem, I was advised to detach the fuse unit and check the multi-plug behind it. Lo and behold, all the internal connectors were a wondrous shade of green! Remembering to disconnect the battery first(!) I set about them with a miniature set of jewellers files until they were restored back to nice shiny brass finish. Problem solved, at least for the last 3 years or so. Also, as it's out of sight, I tightly wrapped the connector in Insulating tape to keep the worst of our beautiful English climate at bay.