Headlight issue

[Keith S]

I have a headlight issue and wanted to see if anyone had some thoughts....

My headlight won't work when plugged in. Here is what I have tested and found so far......

I get 12.72v at the socket without the headlight. I get voltage at the connector under the tank. The battery direct reads 12.82v.

I can run jumper wires from the headlight directly to the battery and it works - both high and low beam.

When I run jumper wires from the connector under the tank, I can get the headlight to work, but the connector is too small to fit both leads into it - so I simply grounded to the bike.

When I run jumper wires from the positive leads - yellow or white - and ground directly to the bike, the headlight works.


When I run jumper wires from the socket in the headlight assembly or simply plug the headlight into the socket - it does not work - remember though, I get 12.72v at the socket. I have cut off the socket and attached blade type connectors to eleminate an issue with the socket - still no luck. As soon as put a load on the circuit (i.e. plug in the headlight), the voltage goes to zero. I have measured it from blade to blade with the headlight plugged in and it is ZERO. Unplug the headlight and measure from the exact same spot and it is 12.72v.:bang: :bang: :bang:


According to the schematic, there is a resistor on the ground wire between the headlight and the first connection. I am assuming the resistor is bad, but can not find the resistor. Does anyone know where it is? If it was not there, the headlight SHOULD work.

Any ideas would be appreciated.

:bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang:

 

[LDO]

Kieth, I know some bikes had a coil of wire on their ground does yours? Maybe that is what you are seeing in the schematic as a resistor?

Big Dog put those in as a 'fix' for some EHC stuff but later found it never really did nuthin....

 

[erldawg]

Almost sounds like a bad ground from the headlight. Did you try jumping in just a ground wire from the socket to the frame?
With power off you could also use an ohm meter and check wires back to source. Just a thought....
My bike has the coil in the headlight bucket.....

 

[stlmikie]

I'm a coil in the bucket guy.

 

[Keith S]

No coil

When I plug in the yellow and white (hi and Lo beam) and then run a jumper wire to a bolt in the headlight bucket, it works.

Obviously, it is the ground wire, but I can not figure out why I get voltage without the light, but nothing with the light.

Does anyone see an issue with just running a ground from the headlight to the bolt in the headlight bucket?

 

[RCAdd1ct]

There is very low current when you are using a voltmeter.

When you try to power the light it needs more current than the bad ground can pass effectively increasing the resistance to where there is a voltage drop (resistor) at the bad ground.