The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 12-10-2009, 07:07 PM   #1
snowblind
Registered User
 
snowblind's Avatar
 
Join Date: Oct 2009
Location: SLC, Utah
Posts: 164
Major headlight upgrade for GMC trucks

Hi everybody.

I thought I would toss this out there for anyone who is interested in upgrading the headlights in their GMC.

I am having a custom wiring harness made that will allow me to run 4 x low/high beam headlights instead of the stock 2 x low/highs and 2 x high only. Installation involves NO CUTTING of the stock wiring. The new harness is custom made to accept the old headlight connectors as the turn on signal for the new relays. Headlight power will now go directly from the alt/battery with minimal current going through the stock headlight switch.

My harness is being made by Susquehanna Motorsports http://www.rallylights.com/ They specialize in rally and race car lighting and use only Hella relays and connectors. I was quoted $130 for one harness. Obviously the price will go down the more harnesses I order.

It would definitely be less expensive to buy the relays separately and wire it all yourself but this will be a slick harness and leave the stock wiring untouched.

Shoot me a PM if anyone is interested in ordering with me.


Matt
__________________
Matt

'72 Jimmy Build
snowblind is offline   Reply With Quote
Old 12-10-2009, 07:13 PM   #2
cdowns
Senior Member
 
cdowns's Avatar
 
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
Re: Major headlight upgrade for GMC trucks

you may run into police problems on the road
__________________
71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane

MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF

DONT BELIEVE EVERYTHING YOU THINK

TAKE MY ADVISE;I DON'T USE IT ANYWAY
cdowns is offline   Reply With Quote
Old 12-10-2009, 07:24 PM   #3
snowblind
Registered User
 
snowblind's Avatar
 
Join Date: Oct 2009
Location: SLC, Utah
Posts: 164
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by cdowns View Post
you may run into police problems on the road
****Off-hwy use only of course****

To avoid bothering other off-hwy drivers I plan to aim one set as low as possible and the other set just a teeny bit higher. I'm not looking to blind anyone I just need more low beam light. I rarely use high-beams.

Is there a DOT law specifically against 4 low beam headlights? I feel like I see people running like that all the time...
__________________
Matt

'72 Jimmy Build
snowblind is offline   Reply With Quote
Old 12-10-2009, 07:26 PM   #4
69GMCLonghorn
Registered User
 
69GMCLonghorn's Avatar
 
Join Date: Dec 2006
Location: Porter Ranch, CA
Posts: 978
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by cdowns View Post
you may run into police problems on the road
From what I understand, you can have 4 headlights on as long as they are not on high beam. I did a similar conversion on my '95 Chevy truck, but kind of backwards... When you hit the high beams, the low beams turned off. The relay setup that I bought for that, allowed all 4 lights to stay on when the high beams came on, but didn't allow for 4 lights on low beam due to the high beam lights not being 2 stage...
69GMCLonghorn is offline   Reply With Quote
Old 12-10-2009, 07:34 PM   #5
snowblind
Registered User
 
snowblind's Avatar
 
Join Date: Oct 2009
Location: SLC, Utah
Posts: 164
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by 69GMCLonghorn View Post
From what I understand, you can have 4 headlights on as long as they are not on high beam.
Isn't the stock set up 4 x high beam and then 2 x on low beam? That's how my Jimmy is and the wiring looks unmolested?
__________________
Matt

'72 Jimmy Build
snowblind is offline   Reply With Quote
Old 12-20-2009, 11:24 PM   #6
mr48chev
Registered User
 
mr48chev's Avatar
 
Join Date: Jul 2007
Location: Toppenish, WA
Posts: 15,708
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by snowblind View Post
Isn't the stock set up 4 x high beam and then 2 x on low beam? That's how my Jimmy is and the wiring looks unmolested?
Yep but it could easily be wired for two low. four high or four low/four high.

All it would take is Two three prong sockets, two extra high beams, a relay to run the inside low beams when you wanted them on and a switch to activate the relay. The power side of the relay would be wired into the low beam circuit. I'd suggest high and low beam relays though to make sure that the extra amps. Plus any lights that throw out extra light would draw more amps.

The lights in my 71 run H-4 bulbs and throw good light but tend to eat dimmer switches.
mr48chev is offline   Reply With Quote
Old 12-10-2009, 08:22 PM   #7
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
Re: Major headlight upgrade for GMC trucks

4 high and 2 low.
I'd bet a kick in the pills that 4 low would not be legal... almost positive.
Just adjusting them alone will do wonders, and then relays and normal haligon sealed beams (I recomend sylvania's silver star) and you will be seeing everything.
Longhorn Man is offline   Reply With Quote
Old 12-10-2009, 08:57 PM   #8
byrd
Union Electrician
 
byrd's Avatar
 
Join Date: Feb 2005
Location: Louisville, Ky.
Posts: 3,354
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by snowblind View Post
Hi everybody.

I thought I would toss this out there for anyone who is interested in upgrading the headlights in their GMC.

I am having a custom wiring harness made that will allow me to run 4 x low/high beam headlights instead of the stock 2 x low/highs and 2 x high only. Installation involves NO CUTTING of the stock wiring. The new harness is custom made to accept the old headlight connectors as the turn on signal for the new relays. Headlight power will now go directly from the alt/battery with minimal current going through the stock headlight switch.

My harness is being made by Susquehanna Motorsports http://www.rallylights.com/ They specialize in rally and race car lighting and use only Hella relays and connectors. I was quoted $130 for one harness. Obviously the price will go down the more harnesses I order.

It would definitely be less expensive to buy the relays separately and wire it all yourself but this will be a slick harness and leave the stock wiring untouched.

Shoot me a PM if anyone is interested in ordering with me.


Matt


Using standard 12 volt auotmotive relays(they sell for around $5-6 bucks/each at Radioshack), and an intenally regulated alt will make a HUGE difference. I will venture to say the candle power was 3-4 times as what it was with the stock set up. There is no need for 4 low beams and I, like longhornman suspect you will have problems with po-po.

BTW LMC sells(others do too just was easier to link to) the premade harness with no splicing for the GMC truck and it is only $30. Get you a internally reg alt conversion and a new alt and you are still out less than the $130 you were quoted and will be legal, and just as bright.

http://www.lmctruck.com/icatalog/cb/full.aspx?Page=74

I have used the harness(took it out as I didn't need it) and found that if you would spend some time making sure all your grounds are excellent and you swap to an internal reg alt, that you really do not need the harness...... jmho...Randy
__________________
69 Custom-10 SWB FLEETSIDE 350/350 TH Dropped 3.5/5.5"
Help support the board->HERE
Board vendors -> Vendors list
Zip:40272
Big Sandy Survivor...

Quote:
We cannot choose the way we die, but we can choose the way we live
Quote:
If you can't fix it with a hammer, you've got an electrical problem.
Quote:
I think Congressmen should wear uniforms like NASCAR drivers so we could identify their corporate sponsors

Last edited by byrd; 12-11-2009 at 10:39 AM.
byrd is offline   Reply With Quote
Old 12-11-2009, 08:52 AM   #9
mrein3
Registered User
 
mrein3's Avatar
 
Join Date: Feb 2000
Location: Center City, MN, USA
Posts: 3,254
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by byrd View Post
Using standard 12 volt auotmotive relays(they sell for around $5-6 buack/each at Radioshack), and an intenally regulated alt will make a HUGE difference. I will venture to say the candle power was 3-4 times as what it was with the stock set up. There is no need for 4 low beams and I, like longhornman suspect you will have problems with po-po.

BTW LMC sells(others do too just was easier to link to) the premade harness with no splicing for the GMC truck and it is only $30. Get you a internally reg alt conversion and a new alt and you are still out less than the $130 you were quoted and will be legal, and just as bright.

http://www.lmctruck.com/icatalog/cb/full.aspx?Page=74

I have used the harness(took it out as I didn't need it) and found that if you would spend some time making sure all your grounds are excellent and you swap to an internal reg alt, that you really do not need the harness...... jmho...Randy
I will disagree with one thing above. You do need to do the relay harness. Without it the factory wiring runs too much current through too small a wire when you turn on your headlights - high beam or low beam. By putting the relays in you are no longer pulling current through over 20 feet of 16 gauge wire to run your headlights. I'm not sure about the linked harness but a decent one will run a 12 or 10 gauge wire from the battery to each relay, then from the hot when energized leg of the relay right to the headlight.

In stock form on my truck I measured 10.5 volts at the headlight. Through relays you're at full battery voltage which is 12 to 14.5 volts (or more if your stock voltage regulator is out of whack. )

All that current drop in the stock wiring produces heat. Heat kills the contacts in your headlight switch.

I wish that pre-made LMC harness was available when I rolled my own harness. I don't have $30 into my setup but time is money. That $30 LMC kit appears to have both relays included which like byrd points out are about $5 each. So you're really only paying $20 for the harness.

As others have pointed out:
1. Do the relay upgrade. (No more burning out your headlight switch)
2. Install halogen sealed beams. (50 state street legal)
3. Adjust your headlights.

Disclaimer: I don't work for or have any financial interest in LMC.
__________________
'70 cab, '71 chassis, 383, TH350, NP205.
'71 Malibu convertible
'72 Malibu hard top
Center City, MN
mrein3 is offline   Reply With Quote
Old 12-11-2009, 02:47 PM   #10
snowblind
Registered User
 
snowblind's Avatar
 
Join Date: Oct 2009
Location: SLC, Utah
Posts: 164
Re: Major headlight upgrade for GMC trucks

Thanks for all the great input guys. I have a 100 amp 1 wire alternator and I will be running Hella "E-code" headlamps with replaceable 55w/65w bulbs.

The reason I want the four lows is because I regularly drive a dark and windy mountain road that is strewn with rocks and boulders. It's usually snowing and the road has regular traffic coming the other way so high beams really aren't an option. In my previous vehicle I ran a pair of the Hella Euro H4 headlights and a set of Micro DE fog lights. The combo was bright and I really liked the sharp cut-off but I still felt the need for more total light.

I don't really want to mount axillary lights on the grill of the Jimmy so I saw this as a decent alternative. Since this harness would be custom I'm thinking I may go one step further and wire the second set of lows on a separate relay. Then I could use a toggle switch to independently turn on the second set of lows.

Thanks for the heads up on the LMC harness. Looking at that link the GMC headlights they sell actually all ship with low/high bulbs but have a wiring adapter that leaves the lows off in the second set!!! If I wasn't going for 4 lows I would probably use that harness and save some money but for me it's really a choice between 4 upgraded lows or 2 upgraded lows PLUS a set of auxiliary lights.
__________________
Matt

'72 Jimmy Build
snowblind is offline   Reply With Quote
Old 12-11-2009, 05:02 PM   #11
JJanzen
Senior Member
 
JJanzen's Avatar
 
Join Date: Feb 2008
Location: Denver, CO
Posts: 252
Re: Major headlight upgrade for GMC trucks

Byrd,
On the LMC harness upgrade, does that run from the external regulator or does it originate from somewhere else. I am just getting to that point on my build and don't yet fully understand the headlight/engine compartment harness/setup. Thanks for the help.
Joel
__________________
Blue72
Red72
JJanzen is offline   Reply With Quote
Old 12-11-2009, 09:18 PM   #12
byrd
Union Electrician
 
byrd's Avatar
 
Join Date: Feb 2005
Location: Louisville, Ky.
Posts: 3,354
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by JJanzen View Post
Byrd,
On the LMC harness upgrade, does that run from the external regulator or does it originate from somewhere else. I am just getting to that point on my build and don't yet fully understand the headlight/engine compartment harness/setup. Thanks for the help.
Joel
The harness directly connects to your battery and plugs into your existing headlight connector and it all works by plug and play. The only part you have to physically connect is to the battery.
You might want to pull the battery out to install the realys behind it on the core support to conceal them, other than that is should take about 15-30 minutes to install the whole set up depending on how much time you spend trying to hide the harness.
__________________
69 Custom-10 SWB FLEETSIDE 350/350 TH Dropped 3.5/5.5"
Help support the board->HERE
Board vendors -> Vendors list
Zip:40272
Big Sandy Survivor...

Quote:
We cannot choose the way we die, but we can choose the way we live
Quote:
If you can't fix it with a hammer, you've got an electrical problem.
Quote:
I think Congressmen should wear uniforms like NASCAR drivers so we could identify their corporate sponsors
byrd is offline   Reply With Quote
Old 12-14-2009, 06:55 PM   #13
snowblind
Registered User
 
snowblind's Avatar
 
Join Date: Oct 2009
Location: SLC, Utah
Posts: 164
Re: Major headlight upgrade for GMC trucks

Hey Everybody.

I wanted to share these photos from yesterday. I discovered another drawback of the stock low beam set up. Snow and ice build up on the high beam when not in use making it pretty much useless when you do need it.



__________________
Matt

'72 Jimmy Build
snowblind is offline   Reply With Quote
Old 12-14-2009, 08:01 PM   #14
Stocker
20' Daredevil (Ret)
 
Stocker's Avatar
 
Join Date: May 2003
Location: Jefferson State
Posts: 13,722
Re: Major headlight upgrade for GMC trucks

Hey.... is that hood cracked open??
__________________
- Mike -

1972 K20 LWB 350/350/205

RIP El Jay
Stocker is offline   Reply With Quote
Old 12-14-2009, 09:20 PM   #15
mrein3
Registered User
 
mrein3's Avatar
 
Join Date: Feb 2000
Location: Center City, MN, USA
Posts: 3,254
Re: Major headlight upgrade for GMC trucks

Quote:
Originally Posted by snowblind View Post
Hey Everybody.

I wanted to share these photos from yesterday. I discovered another drawback of the stock low beam set up. Snow and ice build up on the high beam when not in use making it pretty much useless when you do need it.

pictures snipped
Proving once again that two headlights are better than 4.
JK.

The global warmers out there are right now discovering that all those LED stoplights they installed to save our mother the earth don't melt snow either and now folks are crashing into each other at intersections
http://wcco.com/wireapnewswi/High.ef...2.1363896.html

You can't make this stuff up fast enough.
__________________
'70 cab, '71 chassis, 383, TH350, NP205.
'71 Malibu convertible
'72 Malibu hard top
Center City, MN
mrein3 is offline   Reply With Quote
Old 12-10-2009, 11:31 PM   #16
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
Re: Major headlight upgrade for GMC trucks

Randy, you pointed out something I usually mention, but failed to this time.
Clean the grounds on the core support.
Longhorn Man is offline   Reply With Quote
Old 12-20-2009, 05:38 PM   #17
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
Re: Major headlight upgrade for GMC trucks

you can aim them higher if you want, any direction you feel the need to aim them.
Longhorn Man is offline   Reply With Quote
Reply

Bookmarks

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


All times are GMT -4. The time now is 11:35 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com