Headlight issue (have one hour to fix)

[JerseyJon]

Good afternoon folks. It's a beautiful day here in the greater New York area. Unfortunately, my headlight won't come on, and it's getting dark, and I'm not at dark.

I read the repair threads on the headlight circuit, so I know that they are on the same circuit as the instrument lights. Those don't come on either. I'm probing with the voltage tester probe, and there is power at the headlight relay coming from the red/yellow terminal. I think that the black wire goes to ground but I have no idea where. Any suggestions?

[JerseyJon]

A development.

So I checked the headlight relay with the connector plugged in, power on, engine off. The red/yellow is hot, the other three are dead. Does that mean that I have a bad headlight relay?

[IanDMacDonald]

Fuse? Connector? Relay? RLU?

[JerseyJon]

Fuse is good. Pulling headlight now.

[JerseyJon]

Moving on

So there's no power at any of the three headlight wires (yellow, green or black)

[3Phase]

So there's no power at any of the three headlight wires (yellow, green or black)

Jon,

Hook up a jumper at the Headlight relay connector and see if the lights work.

The Yellow wire with the Red stripe is the hot wire from the Headlight fuse. Put a jumper from that wire to the Blue wire with the Back stripe and hopefully the lights will come on


Wires at the Headlight relay:

Yellow/Red = from Head fuse
Blue/Black = to RLU (Reserve Lighting Unit)
Black = Ground
White = relay coil hot/latch wire from the alternator


.

[JerseyJon]

Thanks Scott

As it turned out, I didn't have any time either on Saturday or Sunday to try Scott's jumper suggestion. Hopefully, I'll get to it this weekend.

One of the most frustrating things, for me, about being a member here and owning an xs11 is that I barely have enough time to ride, let alone tinker, let alone go through the learning curve that we inexperienced mechanics need to go through.

On the other hand, one of the most amazing things about owning an xs11 is that the thing consistently starts, runs, rides, and hauls ass without hardly any input from me.

I'll try messing around with it this weekend.

Jon

[fredintoon]

So I checked the headlight relay with the connector plugged in, power on, engine off. The red/yellow is hot, the other three are dead. Does that mean that I have a bad headlight relay?

Hi Jon,
don't that mean you have a good one? The relay is supposed to turn the headlight on automatically when the alternator starts charging.
The relay will then "latch on" that is the headlight will stay on until the key is turned off even if the alternator stops charging.

[rpgoerlich]

Headlight relay is energized when the alternator starts outputting voltage. So with the Bike running you need to check the voltage on the white wire which will be A/C as opposed to D/C voltage. If yes, the relay is most likely hung up or bad.

If not, you might have a bad diode inline of that white wire which is in the wiring harness under the tank on the RH side not far behind the headlight relay. Mine was visible as it resides in a clear plastic tube with butt connectors on each end(male/female).

[JerseyJon]

Ok gents . . .

Well, thank you guys for all the help so far. Scott, and Richard, I took your suggestions. Richard, the white wire into the headlight relay was hot when the bike was running. So, Scott, I put in a jumper from the white wire to the black and blue wire and voila, the headlight came on.

So here's my analysis, basic as it is.

1) The headlight relay is getting power from the fuse like it should, because the red/yellow is hot when the power is on but the bike is not running.

2) The headlight relay is getting power from the alternator when the bike is running because the white wire is hot when running.

3) The reserve lighting unit is working properly because the headlight came on when I jumped the power from the white wire (from the alternator) to the black/blue wire that goes to the reserve lighting unit. THEREFORE

4) The relay must be bad? Or

5) The black wire from the relay (that's a ground wire, right?) is not grounding properly.

Does anyone know where that black wire from the relay grounds out?

Any other thoughts?

Again, I cannot overstate my gratitude to you all for the knowledge and generosity here.

Jon

[JerseyJon]

Fixed?

So I stuffed a jumper from the white to the black/blue at the connector that plugs into the relay. It seems to work. I'm assuming that there's a loose connection in the relay. And this seems to be a better solution than jumping from the red/yellow to the black/blue, which would potentially drain the battery during startup and when the engine is off but the ignition is on.