Hi.
Im new to this forum game so excuse me if Im a bit wooden getting going.

Anybody had experience with blown headlight bulbs?
Ive got through two sets in a week and have replaced the reg/rec, (was giving 18-19v @2000rpm) and a new battery. Checked as much wiring as I can without performing a full post mortem and still I cant get juice to the headlight bulb connector. (Fuses all ok)

Im pinning hopes on a headlight relay which I ordered from the good folk at www.blackbirdspares.co.uk but in the meantime if anybody has any good tips I'd be grateful.

Cheers. :?:

It sounds like your R/R may have fried things. You seem to be on the right track. Have you checked your relay for proper operation?

Im getting 12v accross the outer two terminals feeding into the relay so with a bit of luck a new unit may sort it. If it doesnt Im back to headscratch mode.

Electrickery - the work of the devil!

cheers.

From what I get out of the wiring diagram.....


The headlamp relay only controls power to the high beam, so with power to two terminals, you're testing the system with the dimmer switch in the "hi" position, and you're fuses, dimmer switch, and starter button are working fine.

The one power input to the relay (Bl/R wire) is sourced from the fuse.

The other power input (Bu) comes directly from the dimmer switch. The dimmer switch is fed through the starter switch, on the same leg that feeds the low beam bulb.


You either have two blown bulbs, or a wiring problem somewhere near the bulbs, or you don't actually have power to two terminals on the headlamp relay. :headscratch:

Have you checked your ground circuits on both the headlamps & the relay? It's the Green wire on the relay, as well as the headlamps.


All years seem to work the same, as well.

I get wood from this forum too. Welcome!

Thanks for your advice on this one.
I will get the circuit tester out again!

Still no sign of the new relay...

The engine start switch also has a set of normally closed contacts supplying power to the headlights. When the starter button is pressed, these contacts open, interrupting power to both headlights and diverting available power to the starter. That is the configuration here in the states, and I admit there might be differences in UK/Euro spec bikes. As a troubleshooting step, I would add this:

1) Turn the ignition switch to ON (it's not necessary to start the bike).

2) Gently wiggle the starter button, without engaging the starter. If the headlights work intermittently, the switch is defective.

This failure mode has appeared on a handful of bikes here in the states, and may play a factor in your troubles. You may be able to make a repair to the switchset, but I opted to replace it in it's entirety. The part is not prohibitively expensive (available at Roy Ayers and other sites), and is an easy repair.

If yours has the flash to pass button on it, don't forget to check it as well. could be stuck and not letting your lights get power.

That's what I already said. :roll:


If both inputs to the relay are there, all of those other switches are conducting.

Well, the relay turned up this morning. Sparkly and new thanks to blackbirdspares.co.uk.
Plugged it in, turned her on and.....nothing.

Tank is coming off tonight and further cable fettling required.
Thanks to everybody for their ideas and tips, northman, jrdxx et al.

Wish me luck.

You might care to just jumper the headlight wires to positive and earth and see if they work then, before you start tearing all hell out of the poor thing.....

Don't despair; I still suspect the starter switch. The headlight relay and dimmer switch are part of the high beam circuit path; the low beam is fed from the fuse with only the starter switch in it's path. Trace the harness from the right side switchset to a coupling in front of the instrument panel (remove the windscreen for better access). disconnect the coupling and use an ohmmeter to probe for continuity between two wires; the Black/Red wire, and the Blue/White wire. When you press the starter switch, the continuity should disappear, under normal circumstances. If you read an open all the time, the switch is bad.

Find the problem, yet?

Aaaaaaaah. and the lord said let there be light.

Deep joy here in the garage. I cant say a big enough THANKYOU for all the advice from you good folk, its really spurred me on and more than that it's identified the root of the problem.
Faulty start switch it was! I did the continuity test across the blue/white and black/red and that was a big wide open. No matter what else I did the juice wasnt geting past there.
I picked up a second hand unit from a breakers, after testing it the same way on his shopbench, then got home connected it up and got a rosy glow.
So its boots on for me tomorrow. Need to put some miles on it to recharge my battery... and the bikes' too.

Once again thanks.
:) :lol:

Glad we were able to help, mate.

This isn't a common failure mode on the Blackbird, but has happened to me and a couple others on this forum-hence the familiarity.

Ride safe. And while you're out, give a nod to Strawberry Fields for me.