Headlights Burned Out - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**special-K** · 10-09-2005, 02:03 PM

I was leaving a friends the other night and he stopped me and said I had a light out.I got out and tapped it and wiggled the connector,didn`t help.Oh well,I figured I`d drive home on Hi-beams.Before I was through the gears,the lights flickered and both went out.So,I quickly hit the dims and same thing,flicker,no light.I had to turn around and go back and borrow a vehicle to get home in.The battery will run down overnight,so I`m disconnecting it.The battery feels warm when I do.What kind of electrical problem could this be?Some thing is shorted,I guess,and there must be too much current in the circuit.Has anyone run intoa similar problem.This is a`72.

**Stocker** · 10-09-2005, 02:15 PM

Quote:

Originally Posted by special-K

there must be too much current in the circuit.

Bingo - I've never had it happen, but it sounds like your voltage regulator is putting out too many volts - that would account for a warm battery and blown out bulbs. Do you have / can you borrow a VOM to check the voltage? I'm not sure, you may not have an external regulator - it may be built into the alternator.

.030over · 10-09-2005, 02:18 PM

First, most common problem is a bad voltage regulator(internal or external). Charging voltage as high as 17-18v will pop some bulbs! Second is bad diodes in the alternator will allow AC voltage to pass through and most DC componants don't like it. Bad diodes will kill the battery in two ways. Diodes will have a draw when engines off and AC voltage will fry it also.
Either way, you replace the alternator!
Scott

Longhorn Man · 10-09-2005, 02:31 PM

The draining of the battery overnight is another sign of a messed up charging circuit.

**special-K** · 10-09-2005, 02:35 PM

Thanks,that was quick!It`s still got the external voltage reg.Nothing else is burned out,yet.I`ve driven it a little since and even with the parking lights on some.I`ll test that out.What`s the benefit of goung to a one wire/internal set-up?Less wiring?It seems everyone I know goes that route.

Longhorn Man · 10-09-2005, 02:37 PM

screw the one wire, just get a GM 3 wire. Cheaper, better, easy to find, cheap to replace.

72MARIO · 10-10-2005, 01:09 PM

I had the same thing happen to me. Only I was 2 hours north from home. A guy that had saw me at a car show that morining 2 hours south noticed my truck anmd took me to his shop. We found the lights in his 55ish ford were the same T3's. Well I made it home with one low beam left.

It was the Alt I changed it no more problems.

A.P. · 10-10-2005, 05:02 PM

Here is some info. if you want to up grade to an internal regulator alternator.
http://www.chevelles.com/techref/tecref14.html
http://www.madelectrical.com/electri...elcoremy.shtml

junkyardjohn · 10-11-2005, 07:28 AM

Quote:

Originally Posted by Longhorn Man

screw the one wire, just get a GM 3 wire. Cheaper, better, easy to find, cheap to replace.

WOW ANDY... ARE WE A LITTLE OPINIATED & JADED THIS MORNING??? I'VE GOT ONE WIRE ALTERNATORS IN ALL THREE OF MY TRUCKS, & THEY WORK GREAT. I JUST BOUGHT A 135 AMP ONE WIRE ALT. AT THE H.A.N. SWAP MEET FOR $55. IS THERE A REASON YOU FEEL THE WAY YOU DO?? OR IS THIS SOMETHING YOU'VE HEARD?? I'VE HAD NOTHING BUT GOOD EXPERIANCES WITH THEM & HAVE BEEN USING THEM EXCLUSIVELY FOR FIVE OR SIX YEARS. MAYBE YOU KNOW SOMETHING THAT THE REST OF US DON'T. HOW ABOUT ENLIGHTENING US?? JOHN

**guyryan100** · 10-11-2005, 08:53 AM

Here's an article about 1 vs 3 wire. Based on this article I went with a 3.

**Stocker** · 10-11-2005, 08:57 AM

Hmmm, can't see the article?

86swb · 10-11-2005, 10:34 AM

Quote:

Originally Posted by guyryan100

Here's an article about 1 vs 3 wire. Based on this article I went with a 3.

Nope, not there.

A.P. · 10-11-2005, 11:23 AM

http://www.madelectrical.com/electri...hreewire.shtml
Here is some info. comparing 1 wire to 3 wire alternator.

10-09-2005, 02:03 PM	#1
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Headlights Burned Out I was leaving a friends the other night and he stopped me and said I had a light out.I got out and tapped it and wiggled the connector,didn`t help.Oh well,I figured I`d drive home on Hi-beams.Before I was through the gears,the lights flickered and both went out.So,I quickly hit the dims and same thing,flicker,no light.I had to turn around and go back and borrow a vehicle to get home in.The battery will run down overnight,so I`m disconnecting it.The battery feels warm when I do.What kind of electrical problem could this be?Some thing is shorted,I guess,and there must be too much current in the circuit.Has anyone run intoa similar problem.This is a`72. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

10-09-2005, 02:18 PM	#3
.030over Junior Member Join Date: Mar 2005 Location: Maryland Posts: 129	Two things... First, most common problem is a bad voltage regulator(internal or external). Charging voltage as high as 17-18v will pop some bulbs! Second is bad diodes in the alternator will allow AC voltage to pass through and most DC componants don't like it. Bad diodes will kill the battery in two ways. Diodes will have a draw when engines off and AC voltage will fry it also. Either way, you replace the alternator! Scott __________________ '67 SWB big block project '85 C60 school bus motorhome conversion

10-09-2005, 02:35 PM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Thanks,that was quick!It`s still got the external voltage reg.Nothing else is burned out,yet.I`ve driven it a little since and even with the parking lights on some.I`ll test that out.What`s the benefit of goung to a one wire/internal set-up?Less wiring?It seems everyone I know goes that route. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

10-10-2005, 01:09 PM	#7
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,052	I had the same thing happen to me. Only I was 2 hours north from home. A guy that had saw me at a car show that morining 2 hours south noticed my truck anmd took me to his shop. We found the lights in his 55ish ford were the same T3's. Well I made it home with one low beam left. It was the Alt I changed it no more problems. __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD

10-11-2005, 08:57 AM	#11
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,694	Hmmm, can't see the article? __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

10-09-2005, 02:31 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	The draining of the battery overnight is another sign of a messed up charging circuit.

10-09-2005, 02:37 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	screw the one wire, just get a GM 3 wire. Cheaper, better, easy to find, cheap to replace.

10-10-2005, 05:02 PM	#8
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	Here is some info. if you want to up grade to an internal regulator alternator. http://www.chevelles.com/techref/tecref14.html http://www.madelectrical.com/electri...elcoremy.shtml

10-11-2005, 08:53 AM	#10
guyryan100 Registered User Join Date: Sep 2001 Location: Cumming, GA Posts: 481	Here's an article about 1 vs 3 wire. Based on this article I went with a 3.

10-11-2005, 11:23 AM	#13
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	http://www.madelectrical.com/electri...hreewire.shtml Here is some info. comparing 1 wire to 3 wire alternator.

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