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 03-29-2023, 10:02 PM   #1
awbanks
Junior Member
 
awbanks's Avatar
 
Join Date: Feb 2023
Location: Brooklyn Park, MN
Posts: 25
Headlights cut out completely after hitting high beam dimmer switch

Took my 71 C20 out for a stroll around the block this evening.
When I hit the dimmer switch for the high beams - the headlights cut out completely.
All other lights are working fine. I didn't dig into the issue tonight. I plan to get back out there tomorrow and see if I can track down a faulty wire or ground.

Any ideas?
__________________
awbanks

1971 C20 Longhorn
awbanks is offline   Reply With Quote
Old 03-29-2023, 10:18 PM   #2
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,268
Re: Headlights cut out completely after hitting high beam dimmer switch

I would start troubleshooting at the highbeam switch. It's common for the terminal connections on the switch to corrode and then the overheat the wiring.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is online now   Reply With Quote
Old 03-29-2023, 10:28 PM   #3
Stocker
20' Daredevil (Ret)
 
Stocker's Avatar
 
Join Date: May 2003
Location: Jefferson State
Posts: 13,688
Re: Headlights cut out completely after hitting high beam dimmer switch

x2 -- the dimmer switch on the floor, aka highbeam switch, lives in a poor environment and is a common failure spot.
__________________
- Mike -

1972 K20 LWB 350/350/205

RIP El Jay
Stocker is offline   Reply With Quote
Old 03-29-2023, 10:38 PM   #4
mr48chev
Registered User
 
mr48chev's Avatar
 
Join Date: Jul 2007
Location: Toppenish, WA
Posts: 15,632
Re: Headlights cut out completely after hitting high beam dimmer switch

If you have higher wattage Halogens in the truck the dimmer switches don't survive well.

I put relays on both low and high beam circuts on my 71 to cut down on the load through the switch (s) After replacing the switch about every four or five months but I am running 55/100 H-4 bulbs.
__________________
Founding member of the too many projects, too little time and money club.

My ongoing truck projects:
48 Chev 3100 that will run a 292 Six.
71 GMC 2500 that is getting a Cad 500 transplant.
77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.
mr48chev is offline   Reply With Quote
Old 03-29-2023, 10:42 PM   #5
cj847
Registered User
 
cj847's Avatar
 
Join Date: Sep 2016
Location: Ozark, MO
Posts: 567
Re: Headlights cut out completely after hitting high beam dimmer switch

I would start by replacing the dimmer switch. They are like $5.
cj847 is offline   Reply With Quote
Old 03-30-2023, 12:07 AM   #6
RustyPile
Registered User
 
RustyPile's Avatar
 
Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,803
Re: Headlights cut out completely after hitting high beam dimmer switch

Quote:
Originally Posted by awbanks View Post
Took my 71 C20 out for a stroll around the block this evening.
When I hit the dimmer switch for the high beams - the headlights cut out completely.
All other lights are working fine. I didn't dig into the issue tonight. I plan to get back out there tomorrow and see if I can track down a faulty wire or ground.

Any ideas?
There are no fuses for the headlights, so don't wear yourself out looking for one. The headlight switch has a built-in circuit breaker that automatically resets itself. Don't use W.A.G. techniques, and parts slinging hoping something sticks. Go here:

http://67-72chevytrucks.com/vboard/s...d.php?t=185856

and download the proper wiring diagram for your truck. Start with the dimmer switch, use a voltmeter or 12V test light to check for continuity, bad switches, bad/corroded connections, burned/broken wires, etc...
RustyPile is offline   Reply With Quote
Old 03-30-2023, 12:13 AM   #7
'68OrangeSunshine
Senior Member
 
'68OrangeSunshine's Avatar
 
Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,419
Re: Headlights cut out completely after hitting high beam dimmer switch

Quote:
Originally Posted by cj847 View Post
I would start by replacing the dimmer switch. They are like $5.
Yeah. LMC lists p/n: 36-0620 for $5.95.
Funny, I needed one right now -- last week -- and bought a Dimmer Switch from O'Reilly's for $26.38. [Incl tax, and w/ Mil Disc]. It was made by Standard and had a ''Lifetime Warranty.''
Still made in Taiwan. [P/N: STD DS72]

The last one was from 7/17, so almost 5 years in a daily driver isn't bad for a part that gets stomped-on multiple times a night.

awbanks: I had your exact gripe, and R&R'ed the Dimmer Switch and that got it.
While you're down there inspect the wiring to the plug and terminals, but most likerly it's just the Switch.
__________________


Every 25 years I like to rebuild that 292, whether it needs it or not.

Last edited by '68OrangeSunshine; 03-30-2023 at 12:19 AM.
'68OrangeSunshine is offline   Reply With Quote
Old 03-30-2023, 12:47 AM   #8
Richard
Senior Member
 
Join Date: Dec 1999
Location: Southern California
Posts: 2,852
Re: Headlights cut out completely after hitting high beam dimmer switch

First thing I would do is check for 12v at the headlights.

From my experience with LMC that $6 switch will be the same or more than Orielly's after shipping, Then there is the issue if it is actually in stock and when they will ship.

The 51 year old switch in my 72 still works. Funny how expectations have changed.
__________________
Richard
1972 K10 Custom Deluxe SWB Fleetside
My build https://67-72chevytrucks.com/vboard/...d.php?t=800746
Richard is offline   Reply With Quote
Old 03-30-2023, 06:59 AM   #9
special-K
Special Order

 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,852
Re: Headlights cut out completely after hitting high beam dimmer switch

I've had good luck with replacing the dimmer switch first. That tends to be the most common cause of your issue. Or to put it differently, the most common sign of a bad dimmer switch is the headlights cancelled out when you hit hi-beams. Don't throw the original out until you see the new one was the fix. If by a less likely chance you have some other issue, you'd be best continuing use of the original. But, mostly likely when to remove that switch you will see it has become right crusty.
__________________
"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 ~
special-K is offline   Reply With Quote
Old 03-30-2023, 09:55 AM   #10
awbanks
Junior Member
 
awbanks's Avatar
 
Join Date: Feb 2023
Location: Brooklyn Park, MN
Posts: 25
Re: Headlights cut out completely after hitting high beam dimmer switch

Quote:
Originally Posted by RustyPile View Post
There are no fuses for the headlights, so don't wear yourself out looking for one. The headlight switch has a built-in circuit breaker that automatically resets itself. Don't use W.A.G. techniques, and parts slinging hoping something sticks. Go here:

http://67-72chevytrucks.com/vboard/s...d.php?t=185856

and download the proper wiring diagram for your truck. Start with the dimmer switch, use a voltmeter or 12V test light to check for continuity, bad switches, bad/corroded connections, burned/broken wires, etc...
Thanks for linking the wiring diagram. That will be a helpful resource. I plan to check with a test light before moving forward with any replacement switches...
__________________
awbanks

1971 C20 Longhorn
awbanks is offline   Reply With Quote
Old 03-30-2023, 09:59 AM   #11
awbanks
Junior Member
 
awbanks's Avatar
 
Join Date: Feb 2023
Location: Brooklyn Park, MN
Posts: 25
Re: Headlights cut out completely after hitting high beam dimmer switch

Quote:
Originally Posted by '68OrangeSunshine View Post
Yeah. LMC lists p/n: 36-0620 for $5.95.
Funny, I needed one right now -- last week -- and bought a Dimmer Switch from O'Reilly's for $26.38. [Incl tax, and w/ Mil Disc]. It was made by Standard and had a ''Lifetime Warranty.''
Still made in Taiwan. [P/N: STD DS72]

The last one was from 7/17, so almost 5 years in a daily driver isn't bad for a part that gets stomped-on multiple times a night.

awbanks: I had your exact gripe, and R&R'ed the Dimmer Switch and that got it.
While you're down there inspect the wiring to the plug and terminals, but most likerly it's just the Switch.
Good to know Orielly has some in stock. I find LMC Truck has some great deals - but sometimes can get you with shipping costs. Looks like they've got it for $5.95 and $5 shipping to me
__________________
awbanks

1971 C20 Longhorn
awbanks is offline   Reply With Quote
Old 03-30-2023, 10:55 AM   #12
melvin
Registered User
 
Join Date: Oct 2006
Location: Sparks, NV
Posts: 18
Re: Headlights cut out completely after hitting high beam dimmer switch

I fought exactly this on my 70 last year. Replaced the switch a couple times and it would work. And then not. And then would. Always lost hi beams. Is it original wiring? Or rewired? My truck was a full frame off, and I used an AAW kit to rewire. On the bulkhead block from the inside of the cab, the little metal tab that holds the terminal in the block was never sprung out enough to catch apparently on the hi beam terminal. So when the engine bay side of the bulkhead block was installed, it pushed that one back just enough that it would barely touch but vibrate a little and intermittently loose contact.
__________________
1970 c10 swb fleetside. Frame off, 2.5/4" drop, LS1/4L60e, daily driver.
melvin is offline   Reply With Quote
Old 03-30-2023, 11:14 AM   #13
72SB
Registered User
 
Join Date: Apr 2022
Location: Moorpark, CA
Posts: 767
Re: Headlights cut out completely after hitting high beam dimmer switch

As mentioned, the dimmer switch on floor is most likely suspect. If it is lose, tighten the hold down screws.

IMHO installing a headlight relay harness is a good idea on any of the 50-70's cars, trucks. LMC sells one. Plug and play, no cutting any wires. It removes the full 12v load off the headlight switch, so headlights and ALL lights are brighter

This is where I installed mine. Just drilled 2 holes to mount relays

.
Attached Images
 
72SB is offline   Reply With Quote
Old 03-30-2023, 12:23 PM   #14
697498chevy
Registered User
 
Join Date: Jan 2009
Location: South Carolina
Posts: 265
Re: Headlights cut out completely after hitting high beam dimmer switch

Lost my headlights in 2011 at 5:30 A.M. My O.E. dimmer switch lasted 42 years . Paid $7 for a new one back then . Been fine ever since . Thanks
697498chevy is offline   Reply With Quote
Old 03-30-2023, 02:12 PM   #15
mrein3
Registered User
 
mrein3's Avatar
 
Join Date: Feb 2000
Location: Center City, MN, USA
Posts: 3,253
Re: Headlights cut out completely after hitting high beam dimmer switch

MN location. (Like me).
Most likely a green, furry dimmer switch connector.

Step 1: Take the connector off the dimmer switch. Look at the connections.
Step 2: Spray with contact cleaner.
Step 3: Re-connect.
You probably just fixed your headlights but I'd do more...

Step 4: As 72SB points out, research this site for "Headlight Relay Upgrade" then roll your own or buy a pre-made wiring harness that uses relays to power your headlights instead of elevendy billion miles of 16 or 18 gauge GM stock wire.

All those miles of stock, too small now dry and brittle wire only gets about 10.5 volts to your headlights.

Using relays to drive your headlights with juice straight off the battery not only puts 14.something volts to your headlights making them brighter, it also saves on your headlight switch which is more money and a larger PITA to replace.
__________________
'70 cab, '71 chassis, 383, TH350, NP205.
'71 Malibu convertible
'72 Malibu hard top
Center City, MN
mrein3 is offline   Reply With Quote
Old 03-30-2023, 06:15 PM   #16
awbanks
Junior Member
 
awbanks's Avatar
 
Join Date: Feb 2023
Location: Brooklyn Park, MN
Posts: 25
Re: Headlights cut out completely after hitting high beam dimmer switch

Thanks everyone for the information! The wiring harness color graphic will be extremely helpful in the future.
It ended up being a faulty dimmer switch. Ended up going with Orielly Auto's replacement for now as 68OrangeSunrise stated and everything works great now.

I did find that the headlight wiring will need some work up front as someone did a poor job of fixing the headlight wire at some point in time.
I will look at adding a relay.

This is why I love this forum! Thank you all for your wisdom and insight.
__________________
awbanks

1971 C20 Longhorn
awbanks is offline   Reply With Quote
Old 03-30-2023, 06:34 PM   #17
Stocker
20' Daredevil (Ret)
 
Stocker's Avatar
 
Join Date: May 2003
Location: Jefferson State
Posts: 13,688
Re: Headlights cut out completely after hitting high beam dimmer switch

Glad you got it fixed, and thanks for the update!

If / when you do the relay mod, you'll need two -- one for low beams, & one for high beams.
__________________
- Mike -

1972 K20 LWB 350/350/205

RIP El Jay
Stocker is offline   Reply With Quote
Old 03-30-2023, 06:44 PM   #18
Arnulfo
Registered User
 
Join Date: Aug 2015
Location: Los angeles
Posts: 160
Re: Headlights cut out completely after hitting high beam dimmer switch

Just went through this. As others have said ,look at the dimmer switch. That was the problem on mine. I took mine apart and cleaned it. Works perfect now. I would try and repair original. They are well made. Good luck
Arnulfo is offline   Reply With Quote
Old 03-30-2023, 09:06 PM   #19
'68OrangeSunshine
Senior Member
 
'68OrangeSunshine's Avatar
 
Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,419
Re: Headlights cut out completely after hitting high beam dimmer switch

Quote:
Originally Posted by awbanks View Post
Thanks everyone for the information! The wiring harness color graphic will be extremely helpful in the future.
It ended up being a faulty dimmer switch. Ended up going with Orielly Auto's replacement for now as 68OrangeSunrise stated and everything works great now.

I did find that the headlight wiring will need some work up front as someone did a poor job of fixing the headlight wire at some point in time.
I will look at adding a relay.

This is why I love this forum! Thank you all for your wisdom and insight.
Happy to help. The 67/72 Forum is a main reason why my Over Fifty trucks still run.
__________________


Every 25 years I like to rebuild that 292, whether it needs it or not.
'68OrangeSunshine is offline   Reply With Quote
Old 03-31-2023, 07:44 AM   #20
MARKDTN
Registered User
 
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,159
Re: Headlights cut out completely after hitting high beam dimmer switch

Just FYI that switch is an AC Delco D808 and can be bought today on Amazon for $12. I don't know if the Delcos are any better than a generic parts store one, but it's an option.
__________________
'83 K20-TPI
'73 C10
'79 C10-ex-diesel(SOLD)
'07 Tahoe(Son driving)
'14 Suburban-DD
'71 C10-current project
MARKDTN is offline   Reply With Quote
Old 03-31-2023, 10:13 AM   #21
Rickjz
Registered User
 
Join Date: Apr 2016
Location: Kirkland,WA
Posts: 67
Re: Headlights cut out completely after hitting high beam dimmer switch

I had this happen on a road trip going through the mountains at night in my 69 Vette. After pressing on the high beam switch a few times the headlights worked again. Probably corrosion in the switch from not being used much.
Rickjz is offline   Reply With Quote
Old 03-31-2023, 05:01 PM   #22
'68OrangeSunshine
Senior Member
 
'68OrangeSunshine's Avatar
 
Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,419
Re: Headlights cut out completely after hitting high beam dimmer switch

I'm going to pull apart the old one [from 2017] and see if it can be refurbished.
Looks like one of the 2 side tangs lost its angle and that allows the cap to come up higher than it should from spring pressure.
In Arizona we see very little corrosion. But the Jimmy, because of its convertible nature has a lot more cabin leaks than the Stepside's cab, even though it's 3 years older.
__________________


Every 25 years I like to rebuild that 292, whether it needs it or not.
'68OrangeSunshine is offline   Reply With Quote
Reply

Bookmarks


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 07:06 PM.


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