Electrical issue - headlight fuse is dead

[rb608]

I posted a story yesterday about having my headlight go out on a ride home. Blown fuse, I assumed, so I got up this morning, opened the fuse cover and checked. Fuse was fine. WTF? Well, I knew I'd be home before dark today, so I just took the bike anyway figuring to trace the problem when I got home. Ha ha. Needless to say, it wasn't a simple as I expected.

Since the aftermarket light bar was also dead, I expected that the problem might be in the headlight housing or the light bar wiring where it's connected to the headlight circuit. Nope. The light bar and headlight wiring appear to be separate and lead back under the tank. Okay fine. Off comes the seat and tank. No help. (Shoulda known that.)

So I finally get the idea to check the fuse panel itself, and whattaya know, there is zero voltage across the headlight fuse. All of the other slots check out fine, but the headlight circuit has nothing.

So apparently the problem is upstream, but it's now too dark, too cold, and I'm too aggravated to keep going. I'll take the cage tomorrow.

But when I dig back into this, I'd love a hint or two where to look for the problem.

[SpoonMan]

Could be the brown and white wire under the tank. If the spotlights are using that wire leg to power up.

[rb608]

Originally Posted by SpoonMan

Could be the brown and white wire under the tank. If the spotlights are using that wire leg to power up.

Would that prevent power to the headlight fuse, or is that downstream?

[Scrapdog2grand]

Your problem is in the fuse box itself, or the Hot Terminal the fuse plugs into is burnt.
Only 2 wires power up those fuses, one is dedicated to the cooling fan, the other hot wire to the other 3 fuses.

[rb608]

Originally Posted by Scrapdog2grand

Your problem is in the fuse box itself, or the Hot Terminal the fuse plugs into is burnt.
Only 2 wires power up those fuses, one is dedicated to the cooling fan, the other hot wire to the other 3 fuses.

That certainly sounds reasonable. Not sure how to get to the backside of the panel though. I removed it from the frame, but getting apart wasn't immediately apparent. Maybe daylight and a cool head will get me there.

[Roach]

When you're checking the voltage at the fuse panel and reading zero, are you measuring across the two terminals with the fuse in or out? Good with fuse in is 0v; good with fuse out is 12v.

What reading do you get on either fuse pin to the negative terminal on the battery? One should be 12v, one should be 0v.

I didn't go look for your other post so I apologize about asking a stupid question... is the head light burnt out?

[rb608]

Originally Posted by Roach

When you're checking the voltage at the fuse panel and reading zero, are you measuring across the two terminals with the fuse in or out? Good with fuse in is 0v; good with fuse out is 12v.

What reading do you get on either fuse pin to the negative terminal on the battery? One should be 12v, one should be 0v.

I didn't go look for your other post so I apologize about asking a stupid question... is the head light burnt out?

With the fuse out, it's 0.0 volts across the fuse slot. The battery is 12+. At first though it was the bulb, but both high and low are out and so is the light bar.

[jpr1968]

Check the contact in the start button. It's probably either corroded or burnt up.

[rb608]

Originally Posted by jpr1968

Check the contact in the start button. It's probably either corroded or burnt up.

Hmm. That sounds easy enough, but why would the headlight wiring run through there?

[jgarib]

I'm no expert and i'm sure someone will correct me if I'm wrong, but I believe most things are routed through the starter and are shut off when the starter is pressed. This way 100% of your load is dedicated to cranking that engine and once cranked (and the button depressed) power is resumed to the rest of the bike.

When adding accessories its wise to add your relays to the wire that comes from the starter so it's load is also cut when the starter is pressed. If not the starter could have less juice when cranking the engine resulting in un-necessary wear.