headlight power wire...????

[guido4198]

1985 FXRS. My headlight has become "intermittent". When it doesn't come on, I get it working by "jiggling" the bundle of wires that runs along the neck, and disappears under the gas tank. Looking inside the headlight bucket, 3 wires come off the headlight insulator..black..which grounds on the inside of the bucket. Yellow and White...both of which run into the left grip "control bundle"  to the hi-beam switch. What I don't know, is which wire in that bundle along the neck actually transmits juice to the headlight.
Anyone have an idea...
Thanks.

[eglideic]

 The White is Hi beam and the Yellow wire is Lo Beam.
I believe the Blue wire supplies power to the Hi/Lo switch from the Ignition Switch.
Does the headlight only flicker when it's on Lo beam or both?

[guido4198]

Both...when it's "off"...neither hi or lo works. After finding the yellow and white running out of the headlight bucket, into the grip bundle, I opened the left grip to see if I could figure out how the power got to the lamp.
Still don't know how that happens..I got the hi beam- lo beam thing figured out...but don't know how the neck bundle figures into the picture.
All I know at this point, is that when the light doesn't come on...If I grab the wire bundle that runs along the left side of the neck and "jiggle" it, the headlight comes on.

[cheetah]

Since the problem is with both the hi and lo light, it sounds like you are loosing ground.
Check the black wire to be sure it is not broken, and making good contact with the frame.
Have seen wire broken in the neck harness if not properly routed causing excess movement as the handlebars are turned and over time will break.
C

[hogpipes1]

You need A ser-manual with wiring dig. ck all the grds. and understand how it all works. hope it not a hot wire broken . it's hot up to that point and can cause the breaker to cut  out if it touches any metal part, burnt wiring, fire, all kinds of nasty things can happen. GOOD LUCK

[HotRock]

Easy check, when the headlight is not working high or low beam it's most likely the ground as said.   Easy to check, just get a short jumper wire and touch one end to the black ground wire from the headlight to a good  chassis ground on the frame/engine side of the bike.   If that corrects the problem and you cannot readily find the loose ground, it may be easier to just run another wire to correct the problem.

[Boe Cole]

I concur on the bad ground.  If the ground is to the triple tree and there is not a ground strap between the front end and the frame, then the ground could be going through the bearings which is a serious problem.  Can ruin the neck bearings in addition to causing the light to flicker.

[messed up]

on my 02 both ground and hot wire were broke inside insulation where they exit the shrink wrap and run under tank, would make contact when wiggled.

[hotroadking]

Pull the headlight, get a digital multimeter, set it to volts.

Turn on the ignition and put the meter ground to a good ground on the bike and
check for power on the yellow (Low) if you have a good 12v reading with the
meter ground direct the frame, then move it (black ground wire from meter) to the black wire in the connector for the bulb.

If when you do this, power on, the meter shows nothing, you have a bad ground, if it shows power, wiggle the harness,

When you wiggle harness with black to harness connector, if power goes out
move the ground back to the frame from the harness and repeat wiggle test, if light remains on with wiggle test and the meter ground wire direct to frame you have a ground problem in the harness.

If when you do this the meter reads no power with the ground to frame you have a power feed issue, broken wire (could be inside a bundle) check connections.

I agree get the SM from a dealer, everything you need is in the book,

[ST40]

I had a similar problem on my Shovel, and it turned out to be the hi-lo switch creating an open or ungrounded circuit, one or the other.  Anyway, replacing it did the trick.  Marty

[guido4198]

Problem Solved...!!
Thanks for all the excellent guidance. After verifying that the ground was solid...I went after the blue "power wire" that runs from a connecting block in the headlight bucket...out the rear of the bucket in a bundle, then along the side of the neck, disappearing under the gas tank.

What I discovered....where the blue wire passed through the plastic "grommet" in the headlight bucket...it had separated inside the insulation.

Pulled out a little more wire, stripped it back @ both ends a bit, and crimped on a "heat shrink" butt splice connecter.

VIOLINS...!!!
Works every time.

Thanks Again.