Question About Headlight Switches
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Question About Headlight Switches
My OEM 7-terminal headlight switch finally gave up last night so I searched for a new switch in the internet. I saw 7 and 8 terminal switches available and I ordered an 8 terminal because I found one for only $11.32. My question is what function did the 8th terminal have? As the switches are otherwise identical I felt I could probably cut the 8th terminal off if it prevents the plug from plugging on. It appears the switches fit over 3000 different G.M. models from the 1960's thru the 1980's.
Melting Slicks
Joined: Feb 2006
Posts: 3,105
Likes: 96
From: Sunrise FL
If you have vacuum operated headlights, those generic switches will not have the extra vacuum switch attached that is needed for vettes.
I found out the hard way, vette switches for C3 are unique, even if others will work to turn the bulbs on and off!!!
So, need to spend a few extra $$
I found out the hard way, vette switches for C3 are unique, even if others will work to turn the bulbs on and off!!!
So, need to spend a few extra $$
Last edited by mikem350; Oct 29, 2015 at 06:02 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
GROUND.
There are 2 different types of Corvette headlight switches from 1968 to 1982. If my memory serves me correctly..the design change took place when GM changed the dash, SO...1968 to 1977 s one design and the 1878 to 1982 is the other.
The 1968 to 1977 USE a METAL strap that goes from the SPEEDOMETER housing to the headlight switch where when the headlight switch is being installed with the HEADLIGHT SWITCH BEZEL...this metal strap goes between the dash and and the headlight switch to provide a GROUND.
The 1978 to 1982 use an actual EXTRA wire in the connector to the headlight switch and the GROUND is coming from a wire in the connector and connects to a terminal that is made into the metal housing of the switch,
DUB
There are 2 different types of Corvette headlight switches from 1968 to 1982. If my memory serves me correctly..the design change took place when GM changed the dash, SO...1968 to 1977 s one design and the 1878 to 1982 is the other.
The 1968 to 1977 USE a METAL strap that goes from the SPEEDOMETER housing to the headlight switch where when the headlight switch is being installed with the HEADLIGHT SWITCH BEZEL...this metal strap goes between the dash and and the headlight switch to provide a GROUND.
The 1978 to 1982 use an actual EXTRA wire in the connector to the headlight switch and the GROUND is coming from a wire in the connector and connects to a terminal that is made into the metal housing of the switch,
DUB
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
According to the applications chart these switches fit over 3000 different G.M. models from the 1960's thru the 1980's with the Corvettes being included. It said it will fit my '71 so I'm wondering what the extra 8th terminal was used for. I held my old switch up to the blown-up picture of my new switch and it appears identical except for that 8th terminal. Many of the G.M. models used hideaway headlights like the '68 Camaro I once owned so hideaway headlights weren't unique to Corvettes. Maybe the 8th terminal turned on a buzzer or a dash light. If that 8th terminal interferes with my plug I'll just snip it off.
Burning Brakes
Joined: Nov 2006
Posts: 954
Likes: 40
2022 C3 of the Year Finalist - Modified
There are 3 DIFFERENT and NON-interchangeable Corvette headlight switches from 68-82.
They are: 68-73, 74-77 and 78-82 switches.
https://www.corvetteforum.com/forums...h-problem.html
Avner
They are: 68-73, 74-77 and 78-82 switches.
https://www.corvetteforum.com/forums...h-problem.html
Avner
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
There are 3 DIFFERENT and NON-interchangeable Corvette headlight switches from 68-82.
They are: 68-73, 74-77 and 78-82 switches.
https://www.corvetteforum.com/forums...h-problem.html
Avner
They are: 68-73, 74-77 and 78-82 switches.
https://www.corvetteforum.com/forums...h-problem.html
Avner
Avner- Did anyone or you figure out what the extra wire was for on the old 166 switches with 8 terminals? I lost track of this.
What is odd is that GM replaced the 8 terminal 166 with a 7 terminal 166, then number changed it to the 191 to work for all cars 68-77. I never have had any issue using the 191 in a 1968-1973 car.
Not to side track this thread... Too broke is looking at the generic switches that do not have the vacuum functioning switch mounted on the side but are often listed by parts houses as being correct... it won't work.
Willcox
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Avner- Did anyone or you figure out what the extra wire was for on the old 166 switches with 8 terminals? I lost track of this.
What is odd is that GM replaced the 8 terminal 166 with a 7 terminal 166, then number changed it to the 191 to work for all cars 68-77. I never have had any issue using the 191 in a 1968-1973 car.
Not to side track this thread... Too broke is looking at the generic switches that do not have the vacuum functioning switch mounted on the side but are often listed by parts houses as being correct... it won't work.
Willcox
I took my OEM switch apart and have all of the components sitting in a coffee can while my new 8-terminal switch is being shipped. If the new switch lacks the vacuum switch feature I'll just remove the base of the new switch and replace it with my OEM base then tell the vendor about the lack of the vacuum switch.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
There are 3 DIFFERENT and NON-interchangeable Corvette headlight switches from 68-82.
They are: 68-73, 74-77 and 78-82 switches.
https://www.corvetteforum.com/forums...h-problem.html
Avner
They are: 68-73, 74-77 and 78-82 switches.
https://www.corvetteforum.com/forums...h-problem.html
Avner
DUB
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Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Yep, the new HLS6 (#1995122) headlight switch WAS wrong as it didn't have the 2-nipple vacuum valve on the base plate. As only my dimmer rheostat had failed I swapped the new rheostat onto my OEM switch and now it works perfectly. I e-mailed the seller and told him his switches will not fit 1968 thru 1982 Corvettes so hopefully he'll change his applications chart.