Ground connection from headlight

[Rust_to_Redemption]

Went to go for a ride a couple days back, and the headlight refused to turn on. Everything else functioned properly (tail light, brake light, all turn signals, etc). Replaced the bulb, still no light. Opened up the wiring harness and the ground connection from the 4 way split was damaged (see picture). I respliced the line together and checked that the connection to the ground was still good, but still no light. Dimmer switch problem? Any other ideas?

[chuck hahn]

C heck where the plug wires and the plug itself join. I have had connectors that looked fine but when you wiggle them theres a problem. I strip, recrimp, and solder the joints when found. Little shrink tubing and it all good again.

[jdion81]

High beam work? Looking at the diagram, the high beam indicator should light regardless of whether the connection to the bulb is working. You probably know this, the speedo and tach light are powered by the same + connection. Follow the yellow dashed line from the dimmer switch back to the connector and it looks like there is a splice or Y connection at the connector. May be a good place for a wiring failure.

[Steve]

The most obvious place to look would be the bulb itself. Jdion asked if the high beam worked. That will verify that the fuse is good and getting power to the dimmer switch, but if the low beam filament is out, it won't matter how good the rest of your connections are, it simply won't work.

[Redman]

As others have said, if high beam indicator on instruments work then know fuse is good and hi-lo switch is good.
and then focusing on the ground is a good idea since both hi and low do not work.

any further troubleshooting without a meter (or test probe light) is going to be a shot-in-the-dark (pun intend).

good that you have schematic, so know wire color for hi (yel) and lo (wht) and ground.

get a meter (or test probe light).

[Rust_to_Redemption]

The most obvious place to look would be the bulb itself. Jdion asked if the high beam worked. That will verify that the fuse is good and getting power to the dimmer switch, but if the low beam filament is out, it won't matter how good the rest of your connections are, it simply won't work.

Replaced the bulb with a new one, would hope the low beam filament would be ok on a brand new bulb. I checked the fuse and it was not blown. The problem may be somewhere in the wiring between the dimmer switch and bulb?

[Rust_to_Redemption]

High beam work? Looking at the diagram, the high beam indicator should light regardless of whether the connection to the bulb is working. You probably know this, the speedo and tach light are powered by the same + connection. Follow the yellow dashed line from the dimmer switch back to the connector and it looks like there is a splice or Y connection at the connector. May be a good place for a wiring failure.

High beam indicator lights up on the dash, but no high beam. Looks like I'll be chasing down a wiring issue in the near future.

[Steve]

Easiest way is to follow Redman's advice and the advice in Nessism's signature: "To measure is to know".

In this case, you don't need to measure the volts with a meter to know whether you have 14.3 or 12.9 volts, you just need a test light that you can poke into the connector to see if it comes on. Quick, easy, cheap. I probably use a test light a LOT more than a voltmeter when diagnosing problems like this.

Connect the ground clip to the battery or a good chassis ground. Poke the probe into the headlight socket. The top terminal is the low beam, the right side (if you could see it while riding) is the high beam. The left terminal is the ground. If you have power there, you will have to diagnose the ground side.

.

[Rust_to_Redemption]

Got it. Looks like I will be making a stop to get a test light on the way home.

[posplayr]

Got it. Looks like I will be making a stop to get a test light on the way home.

You should buy a voltmeter.

[Rust_to_Redemption]

Have one. Test light sounds faster? Just ground it, prod the connection you want to check, and move along if it lights up.

[Redman]

Have one. Test light sounds faster? Just ground it, prod the connection you want to check, and move along if it lights up.

Yes and No.

Depending on what you mean by "ground it".

If you mean to connect the tester ground to the nearby ground wire: If do detect voltage at a particular point, then Yes, move on to next point, and you know the ground wire is in fact a ground. If do not detect voltage at a particular point, try it again with tester ground wire on battery negative or good frame ground, if then do detect voltage at that same point then know the problem is that the ground wire is not really a ground.

If you mean to connect the tester ground to battery negitive or a good ground: If do not detect voltage at a particular point, then Yes, move on to another point. If do find voltage on, say, the headlight but the head light doesnt light, then move the tester ground to the the headlight ground wire. .... .....

[Rust_to_Redemption]

Found the problem. Bad ground wire connection between chassis ground point and headlight. Re-attached, soldered, and sleeved; works good as new again. Thanks for the replies everyone, very helpful for a non-electrically inclined person such as myself.

[Steve]

Did you find that with the test light?

.

[Rust_to_Redemption]

Did you find that with the test light?

.

It helped demonstrate the problem was with the grounding wire, so circuitously I guess so? For 9 bucks, being able to prod around so easily to check if something has juice or not, it was definitely worth the purchase price. Wish I had had one when I was originally fixing all of the awful electrical mods the PO made.