Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 04-09-2020, 12:47 AM   #1
Paul Bennett
Senior Member
 
Join Date: Sep 2016
Posts: 628
Default 12v Headlight problem

I bought a set of 7" 12v headlights and found the hi and low beam filaments joined instead of being two separate filaments with a common ground. The result when applying voltage to the hi beam filament, voltage became available at the low beam filament contact as well. And visa versa.

The only solution is to use a relay to power hi and low beams. Wiring directly to the headlight just as the 6v lights were wired causes the red dash hi beam indicator bulb to light in both hi and low positions. BTDT

My question is regarding the bulb filament. Has anyone ever gotten into a 12v sealed beam to understand the physical difference of between a 6v and a 12v bulb filament?
Paul Bennett is offline   Reply With Quote
Old 04-09-2020, 10:23 AM   #2
38bill
Senior Member
 
38bill's Avatar
 
Join Date: Apr 2014
Location: Minnesota
Posts: 1,162
Default Re: 12v Headlight problem

Positive or neg ground? I'm no electrical engineer but I'm guessing that the ground is mixed up.
38bill is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 04-09-2020, 12:31 PM   #3
51 MERC-CT
Senior Member
 
51 MERC-CT's Avatar
 
Join Date: May 2010
Location: East Hartford, Ct
Posts: 5,898
Default Re: 12v Headlight problem

Quote:
Originally Posted by Paul Bennett View Post
I bought a set of 7" 12v headlights and found the hi and low beam filaments joined instead of being two separate filaments with a common ground. The result when applying voltage to the hi beam filament, voltage became available at the low beam filament contact as well. And visa versa.

The only solution is to use a relay to power hi and low beams. Wiring directly to the headlight just as the 6v lights were wired causes the red dash hi beam indicator bulb to light in both hi and low positions. BTDT

My question is regarding the bulb filament. Has anyone ever gotten into a 12v sealed beam to understand the physical difference of between a 6v and a 12v bulb filament?
I have installed 12 volt sealed beams as a replacement for 6 volt sealed beams.
The original 3 prong 6 volt receptacle is identical to the 12 volt.
There should not be any issues with high/low beam function.
I suspect that if any wiring was replaced or altered, that is where the problem exists.
Also check the wiring and functionality of the dimmer switch.
__________________
DON'T RECALL DOING SOMETHING FOR MYSELF BASED ON SOMEONE ELSE'S LIKES OR DISLIKES

Last edited by 51 MERC-CT; 04-09-2020 at 01:00 PM.
51 MERC-CT is offline   Reply With Quote
Old 04-09-2020, 12:36 PM   #4
41ford1
Senior Member
 
41ford1's Avatar
 
Join Date: May 2010
Location: ManchVegas, New Hampshah
Posts: 1,589
Default Re: 12v Headlight problem

This diagram shows the socket function. The High and low beam filaments are connected to a common ground. There will be a problem only if one of the headlights loses a ground. The power will back feed to the other lamp to seek a ground. this is the same for both 6v and 12v.
Attached Images
File Type: jpg H4 socket.jpg (21.8 KB, 25 views)
__________________
You are never to old to enjoy your childhood.

Forty1fordpickup on the HAMB.
41ford1 is offline   Reply With Quote
Old 04-09-2020, 01:10 PM   #5
Bob C
Senior Member
 
Join Date: May 2010
Location: So Cal
Posts: 8,711
Default Re: 12v Headlight problem

I'd check for a bad ground.
Bob C is offline   Reply With Quote
Old 04-10-2020, 06:41 AM   #6
PeteVS
Senior Member
 
PeteVS's Avatar
 
Join Date: May 2010
Location: FP, NJ
Posts: 2,769
Default Re: 12v Headlight problem

Sponsored Links (Register now to hide all advertisements)
Bad grounds account for "bewildering" things happen. One of them is that the tail light will work on both sides, but when you step on the brake, only one will work and the tail light on the other side will go out.
__________________
Don't never get rid of nuthin!
PeteVS is offline   Reply With Quote
Old 04-11-2020, 07:52 AM   #7
Paul Bennett
Senior Member
 
Join Date: Sep 2016
Posts: 628
Default Re: 12v Headlight problem

I put a 12v 7" sealed beam bulb on a clean workbench with a 12v battery and voltmeter. Connect battery -12v to the ground terminal of the bulb per diagram above and +12v to the hi beam terminal. The lamp lights and +12v comes out of the low beam terminal enuf juice to light another bulb.


Nothing to do with grounds or old wiring. I'm interested in knowing why when I apply voltage to either hi or low beam terminals, voltage appears at the other terminal.
If I apply voltage to a 6v bulb NO VOLTAGE appears at the other terminal.


Guys, if a chicken died in the back seat of an '35 Ford at 25mph, someone would claim it had a bad ground. Please concentrate on the 12v bulb if you have ever messed with one. (and forget ground)



Thanks 41F1 for the nice socket diagram.
Paul Bennett is offline   Reply With Quote
Old 04-11-2020, 08:19 AM   #8
1931 flamingo
Senior Member
 
1931 flamingo's Avatar
 
Join Date: May 2010
Location: new britain,ct 06052
Posts: 9,389
Default Re: 12v Headlight problem

I'd try another bulb or manufacturer.
Paul in CT
1931 flamingo is offline   Reply With Quote
Old 04-11-2020, 09:03 AM   #9
51 MERC-CT
Senior Member
 
51 MERC-CT's Avatar
 
Join Date: May 2010
Location: East Hartford, Ct
Posts: 5,898
Default Re: 12v Headlight problem

Quote:
Originally Posted by Paul Bennett View Post
I put a 12v 7" sealed beam bulb on a clean workbench with a 12v battery and voltmeter. Connect battery -12v to the ground terminal of the bulb per diagram above and +12v to the hi beam terminal. The lamp lights and +12v comes out of the low beam terminal enuf juice to light another bulb.
Just did the same procedure ( without the clean workbench)
This is with a Sylvania H6024 halogen sealed beam, high beam on, ZERO voltage from the low beam terminal.
At this point it sounds like an anomaly with the bulb.
__________________
DON'T RECALL DOING SOMETHING FOR MYSELF BASED ON SOMEONE ELSE'S LIKES OR DISLIKES
51 MERC-CT is offline   Reply With Quote
Old 04-11-2020, 09:37 AM   #10
KGS
Senior Member
 
KGS's Avatar
 
Join Date: May 2010
Location: Schooley's Mountain
Posts: 530
Default Re: 12v Headlight problem

I had a set of those Sylvania Halogen bulbs some years ago in a 280Z.
On low beam, only the low beam filament lit up. On high beam, both filaments lit up. Brighter lights that way and if I remember correctly, they were advertised to do that.
Ken
KGS is offline   Reply With Quote
Old 04-11-2020, 10:01 AM   #11
51woodie
Senior Member
 
51woodie's Avatar
 
Join Date: Apr 2018
Location: Chelmsford, ON Canada
Posts: 524
Default Re: 12v Headlight problem

What lamp numbers are being tested? Unless there is some internal component, such as a diode, I'm not sure how both filaments would come on at the same time on high beam and not on low beam. You have to consider that I am analysing this as mechanic. The manufacturer may be using the same principal as used for three-way lights in your living room, to get a brighter headlamp.


How do you get three levels of lighting with two filaments?
Low = 50W
Med=100
High= 150W (two filaments 50+100 on at the same time, controlled by the switch)
51woodie is offline   Reply With Quote
Old 04-11-2020, 10:48 AM   #12
cas3
Senior Member
 
Join Date: Jan 2011
Location: sw minnesota
Posts: 4,541
Default Re: 12v Headlight problem

that image posted above is looking at the front, or open end of the plug, now looking at the rear of the bulb is a mirror image, ground on the left, high on the right. is that how you hooked up your test?
cas3 is offline   Reply With Quote
Old 04-11-2020, 11:25 PM   #13
Paul Bennett
Senior Member
 
Join Date: Sep 2016
Posts: 628
Default Re: 12v Headlight problem

Thanks - I'm going to rebuy some bulbs (Sylvania H6024) as it sounds like I got a pair of strange ones.

Last edited by Paul Bennett; 04-14-2020 at 08:35 AM.
Paul Bennett is offline   Reply With Quote
Old 06-06-2020, 09:48 PM   #14
Paul Bennett
Senior Member
 
Join Date: Sep 2016
Posts: 628
Default Re: 12v Headlight problem

I finally got around to finishing the research, starting with purchase of a Sylania H6024. Sorry but I don't recall the manufacturer of the near idential bulbs with problems. Recall those problem was that the dash speedometer RED hi beam indicator light, lit on both hi and low beams positions. I'm a mile away from my garage and will get the mfgr data later (and post it here).


Bottom line, the Sylvania has totally indepentant halogen high and low beams filaments within the bulb. The generic over-the-counter halogen 7" blub have a common something so that when applying voltage to ground and low beam terminals, 12v squirts from the high beam terminal as well even though no voltage was sent to that terminal from the switch.


Time to order a matching bulb for the other side.
Paul Bennett is offline   Reply With Quote
Old 06-07-2020, 01:29 PM   #15
JSeery
Member Emeritus
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 16,132
Default Re: 12v Headlight problem

Quote:
Originally Posted by Paul Bennett View Post
The generic over-the-counter halogen 7" blub have a common something so that when applying voltage to ground and low beam terminals, 12v squirts from the high beam terminal as well even though no voltage was sent to that terminal from the switch.
Couldn't resist, that sounds like a grounding problem!
JSeery is offline   Reply With Quote
Old 06-07-2020, 04:16 PM   #16
terry
Senior Member
 
Join Date: May 2010
Posts: 260
Default Re: 12v Headlight problem

And I'd hate to be that chicken in the back seat! Terry
terry is offline   Reply With Quote
Old 06-07-2020, 05:23 PM   #17
Lanny
Senior Member
 
Lanny's Avatar
 
Join Date: May 2010
Location: Mn
Posts: 2,402
Default Re: 12v Headlight problem

Here is a picture of a 12v headlamp wiring.

click on picture to Enlarge
Attached Images
File Type: jpg wireing 3 prong 12 volt headlight.jpg (40.1 KB, 29 views)
__________________
My Wife Says That I Never Listen to Her,
I Think That's What She Said


If mama ain't happy, ain't nobody happy.
But if daddy ain't happy...RUN
Lanny is offline   Reply With Quote
Old 06-07-2020, 07:24 PM   #18
richard crow
Senior Member
 
Join Date: May 2010
Posts: 1,762
Default Re: 12v Headlight problem

when you are on low beam one filerment is lit when you go to high beam both filerments are lit.
richard crow is offline   Reply With Quote
Old 06-07-2020, 08:44 PM   #19
rich b
Senior Member
 
rich b's Avatar
 
Join Date: May 2010
Location: Minnesota
Posts: 1,813
Default Re: 12v Headlight problem

Quote:
Originally Posted by richard crow View Post
when you are on low beam one filerment is lit when you go to high beam both filerments are lit.
Not usually.
rich b is offline   Reply With Quote
Old 06-07-2020, 09:31 PM   #20
Lanny
Senior Member
 
Lanny's Avatar
 
Join Date: May 2010
Location: Mn
Posts: 2,402
Default Re: 12v Headlight problem

On my '65 Fastback, when the lights are on dim, Only the dim wire has power.
When the headlights are on bright, Only the bright wire has power.
And Only one filement lights up at a time.


.
__________________
My Wife Says That I Never Listen to Her,
I Think That's What She Said


If mama ain't happy, ain't nobody happy.
But if daddy ain't happy...RUN
Lanny is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 03:29 AM.