Headlight/Hi Beam Issue
Thread Starter
6th Gear
Joined: Oct 2024
Posts: 6
Likes: 1
From: Illinois
Headlight/Hi Beam Issue
Hey Everyone, very excited to be apart of the C3 community. You may think I'm a moron but I sold my C7,to get into a C3. After all this is the car I fell in love with as a kid. I've been reading the forums and getting a few electrical issues cleaned up. My issue is this in my 75', I have new headlights-both hi beam and low beam. Low beams come on great, when I switch to high beam, the hi beams come on, but the passenger side low beam turn off.....I have a headlight switch that was replaced two years ago. I also replaced the hi beam/low beam dimmer switch on the floor, same issue.
What am I missing? Do I need to hunt down a relay? Thanks in advance
What am I missing? Do I need to hunt down a relay? Thanks in advance
Racer
Joined: Jul 2018
Posts: 331
Likes: 123
From: Sandusky, OH
Welcome!
Flow Chart to diagnose any electrical issues for your Corvette:
Corvettes—-Electrical problem—-Ground problem
My ‘71 headlamps were goofy. Cleaned connections at headlamps and the problem disappeared.
Enjoy the discoveries!
Steve O.
Flow Chart to diagnose any electrical issues for your Corvette:
Corvettes—-Electrical problem—-Ground problem
My ‘71 headlamps were goofy. Cleaned connections at headlamps and the problem disappeared.
Enjoy the discoveries!
Steve O.
Melting Slicks
Joined: May 2021
Posts: 2,289
Likes: 1,329
From: Fleming Island, FL
The low beam headlight has two filaments. One for low beam and one for high beam. Probably the low beam filament is burnt out or a bad electrical connection to that headlight. Try wiggling the connector on the back of that headlamp.
Team Owner
Joined: Jun 2001
Posts: 23,381
Likes: 1,067
From: Virginia USA
Also might want to upgrade to relays as our cars don't have them. All the current runs through the switch. There are threads on how to do it. When you do you upgrade the wire gauge to the lamps so you can run higher wattage bulbs or halogens.
Safety Car
Joined: May 2001
Posts: 4,761
Likes: 1,648
From: Fairfax Virginia
Welcome to the Corvette Forum mhhanson!
This is clearly the right place when you have questions regarding a Corvette! It must have bee a big change going from a C7 back to a C3! The First of the C3's was one of the coolest cars I saw while growing up. I now have a 1968 C3 convertible with a 427 L88 clone and 4 speed and a 1988 Corvette Coupe with it's L98 engine. Both great cars and yet hugely different in so many ways! Going 3 generations back must have been a tough change for you.
Without this Corvette Forum, I would be looking other places for information that I seek and it was much harder before The Corvette Forum! This forum lets you hear from people with experience that are willing to help you out and the whole system works. I learned so much here on this forum that now I feel confident to help others with their problems. It is awesome to be able to ask virtually any Corvette question and get answers from members all over the world. I know that the 1975 Corvettes are well represented here on this Forum so you are going to get the answers you seek from experienced owners.
You were able to resolve your headlight issue so you are off to a great start!
Dirty connections can plague Corvettes. I like to remove wires and clean the connections and the re secure them with battery grease to keep the oxygen out to prevent corrosion. Especially the ground wire that connects to the frame from the battery negative post. I use DeOxIt to clean my connectors now and it will remove 50+ years of corrosion off in seconds. Getting the connections clean can make the entire wiring system work better. I cleaned the light bulb sockets and the bulbs seemed to shine brighter.
At some time you might measure the voltage at the headlamp while they are on. It should be closer to full battery voltage (above 13.5 volts while driving) but since they wired the Corvettes the way they did back then you frequently find below 12 volts at the headlights under way. Having a relay would allow your lights to see battery voltage and potentially make up to 30% more light output if it is wired properly. I have done this to other cars which burn out the headlight switches and the results are amazing, 30% more light doesn't sound like much until it is dark. If you change the type of headlight to one that uses more power be sure to up-size the wires to protect your wiring harness. There are companies who make the whole harness for the headlight system but they are pricey. Speed Direct offers new halogen lights with a harness and they want a mere $968.35 for the kit. I made my harness modifications based on their design for the wiring harness.
This is clearly the right place when you have questions regarding a Corvette! It must have bee a big change going from a C7 back to a C3! The First of the C3's was one of the coolest cars I saw while growing up. I now have a 1968 C3 convertible with a 427 L88 clone and 4 speed and a 1988 Corvette Coupe with it's L98 engine. Both great cars and yet hugely different in so many ways! Going 3 generations back must have been a tough change for you.
Without this Corvette Forum, I would be looking other places for information that I seek and it was much harder before The Corvette Forum! This forum lets you hear from people with experience that are willing to help you out and the whole system works. I learned so much here on this forum that now I feel confident to help others with their problems. It is awesome to be able to ask virtually any Corvette question and get answers from members all over the world. I know that the 1975 Corvettes are well represented here on this Forum so you are going to get the answers you seek from experienced owners.
You were able to resolve your headlight issue so you are off to a great start!
Dirty connections can plague Corvettes. I like to remove wires and clean the connections and the re secure them with battery grease to keep the oxygen out to prevent corrosion. Especially the ground wire that connects to the frame from the battery negative post. I use DeOxIt to clean my connectors now and it will remove 50+ years of corrosion off in seconds. Getting the connections clean can make the entire wiring system work better. I cleaned the light bulb sockets and the bulbs seemed to shine brighter.
At some time you might measure the voltage at the headlamp while they are on. It should be closer to full battery voltage (above 13.5 volts while driving) but since they wired the Corvettes the way they did back then you frequently find below 12 volts at the headlights under way. Having a relay would allow your lights to see battery voltage and potentially make up to 30% more light output if it is wired properly. I have done this to other cars which burn out the headlight switches and the results are amazing, 30% more light doesn't sound like much until it is dark. If you change the type of headlight to one that uses more power be sure to up-size the wires to protect your wiring harness. There are companies who make the whole harness for the headlight system but they are pricey. Speed Direct offers new halogen lights with a harness and they want a mere $968.35 for the kit. I made my harness modifications based on their design for the wiring harness.
Last edited by ctmccloskey; Oct 16, 2024 at 03:51 PM.
