Headlight has me stumped!! (Solved)

[Jabba]

The socket tests good with 12v to each terminal in either bright or dim.

The bulb tests good when I put 12v to each of the bright and dim terminals.

But when I plug them together, I get no BRIGHT headlight.  Dim still works.  

WTF?

Anyone got any ideas?  It SEEMS like they are all together real good and tight.

Jabba

[jer0177]

The female spade connector inside the socket may not be making contact with the male spade connector on the bulb sufficiently to light it up.

Use a pick or small screwdriver (think glasses small) and pop out the connecter from the socket and tighten down the sides of it a bit, adjust the retaining tab and put it back into the socket and see if that works.

[Chrisj CMA]

squirt some WD40 into the high beam switch and function it several times.  If it comes back to life, take it apart and clean it and dilactic lube it

[Jabba]

There is 12v at the SOCKET when the switch is in high beam.  It ain't the switch.  The socket tests 12v appropriately at both the dim and bright connectors. 

And the bulb lights both bright and dim... but not when plugged together.

Everything seems tight, and I did go tweak the female parts of the connector tighter.

It doesn't make ANY sense to me.

Jabba

[jer0177]

Try a spare bulb just for poops and giggles? 

[tank_post142]

just because there is 12 volts there does not mean it has sufficient amperage to light the bulb. do what Chris says and clean the switch well then check again. I'd open the switch and clean it proper.

[Jabba]

Aight!!

I'll service the switch.

I ain't got a spare lying around.

I skeptical, but I have been wrong about a LOT of stuff like this in my life...

Stay tuned.

Jabba

[R J]

The socket tests good with 12v to each terminal in either bright or dim.

The bulb tests good when I put 12v to each of the bright and dim terminals.

But when I plug them together, I get no BRIGHT headlight.  Dim still works.   

WTF?

Anyone got any ideas?  It SEEMS like they are all together real good and tight.

Jabba

Hey good buddy, but I think you might have a GROUND problem.    Trace the ground back and make sure it isn't corroded for the hi beam.  When you use your tester you are making a differnt ground.

Laugh all ya want, but I chased something of this nature for 3 days in the shop a few years ago.    Finally found a corroded connector causing the problem.

[tank_post142]

see don't you feel better?    check that grd like rj says too. it has to be crappy connections from the switch out to the light to grd.

[Jabba]

There is a ground wire that is part of the plug right?  There are connectors at 3:00, 6:00 and 9:00.  The 9:00 is the ground.  6:00 is dim, and 3:00 is bright.  It all tests good.  I just serviced the switch too, and spent most of the time looking for one of the little brass screws that evaporated when it hit my garage floor.  Damn it.

Got everything back together, and still tests prefect both on the bench and at the headlight connector with a meter, but not when I plug them together.  I also tightened up the female parts again too.
 

OK RJ... I'll go chase the ground now.  I ain't HAPPY about it though!

To paraphrase RJ... "It firkin' HOT out there!"

Jabba

[Gryphon Rider]

When a circuit has an high resistance component, such as a poor connection, it could very well test at the proper voltage when putting a gauge (or low wattage test light) on it.  It's when you try to send a higher current through it by adding the headlight that you get a large voltage drop at the poor connection, and thus the headlight will either be very dim, or perhaps not light at all.

[Robert]

A easy test, plug the bulb in and see if all the wires have power or 2 have power if all three have power then the ground is bad. Take the test light and use the ground in the plug to test with rather than a separate ground. The bulb uses a common ground so that means the power will back feed through the element that isn't on and the bulb will light. It will not be as bright but it will light the fact that the bulb doesn't light that brightly shows there is a bad ground.

[Jabba]

When a circuit has an high resistance component, such as a poor connection, it could very well test at the proper voltage when putting a gauge (or low wattage test light) on it.  It's when you try to send a higher current through it by adding the headlight that you get a large voltage drop at the poor connection, and thus the headlight will either be very dim, or perhaps not light at all.

Yep.  Figured this out just now.  Came in here and you beat me to it.

There is 12v when unplugged but nada when i plug it in.

I guess I am getting BACK into the switch.

Jabba

[Jabba]

It was just a bad connection inside one of the connectors inside the headlight cover.

It's all good now.

Dang it.  3 hours douwn the dang drain for THAT!!   

Jabba

[jer0177]

It was just a bad connection inside one of the connectors inside the headlight cover.

It's all good now.

Dang it.  3 hours douwn the dang drain for THAT!!   

Jabba

Glad you found it.  Sometimes you're the bird, sometimes you're the windshield.   

[old2soon]

             

It was just a bad connection inside one of the connectors inside the headlight cover.

It's all good now.

Dang it.  3 hours douwn the dang drain for THAT!!   

Jabba

  Better your three hours than the dealer. My guys here in the Show Me go fer $65.00 an hour. I can buy a LOT of gasoline or bling fer that kinda money. Now doncha feel lots better that YOU (with the help of this fine forum) fixed it and it's all good. And you know a little more bout yer fat gal. RIDE SAFE.

[Jabba]

Yeah... I knew I'd get it eventually, but it's like 1000*F here today, and humid.  I am sure you know it.  Fat red haired guys like me evolved in the North.

And now I know more about my soon to be someone else's fat Lady.

I about got all the crap off her that's gonna fall off.  I guess I'll put her up for sale.

Jabba