Topic: 78 CB550 Headlight Went out

[Y00B@99]

     Hi folks. Recently my Headlight went out, so I ordered a new headlight as well as the accompany wires to the bulb. Got new connectors, to connect to the existing wiring harness; I plugged them in, and still no light. All of my other lights work: Signals; oil; neutral.
     Anyone have an idea as to why it isn't working?

[KennyRedman]

Check the fuse?

[Y00B@99]

    Hi; what in the fuse should I be looking for? Any particular signs I should keep a heads up for?

[KennyRedman]

There are three fuses, one for the headlight (7A), one for the taillight (7A), and a main one (15A). You should have two spares also. Take it out and see if it’s blown- if it is, the metal strip inside will be broken, as it can only take so many amps and you’ll have to replace it. If it keeps blowing, you’ll want to find out what’s causing it. If the fuse is in good condition, then you have a broken wire or loose connection, or bad ground perhaps. Hard to say.

Here’s your manual. The wiring diagram is at the end:

http://manuals.sohc4.net/cb550/owners_manual/OM55078.pdf

[Y00B@99]

    Awesome. Thank you much!
Kind regards.

[seanbarney41]

sometimes these old fuses are not visibly blown, so even if it looks ok try swapping in a known good fuse or check with a meter.

Another likely failure is your starter button...when button is depressed it is supposed to cut power to headlight, then re-light it when button is released.  This is a known weak link on bikes with no headlight on/off switch.  Sometimes just a spray of electrical contact cleaner is all it needs.

[Y00B@99]

    @KennyRedman @seanbarney41
    Thank you folks much. Fuse turned out to be the problem. Switched it out and presto.
Kind regards.