Headlights fail
Thread Starter
Racer
Joined: Aug 2018
Posts: 380
Likes: 170
From: Erath County Texas
Headlights fail
A rare running with headlights for more than 10-15 minutes to "get home" last week for a (what's become rare) car show (these days) .... early morning drive. (I know, risky)
with the BRIGHTS on for approx 10 minutes/so, the headlights started to fail ... I de-selected the BRIGHT and the low beam lamps operated continuously. After a few minutes of "cool down" I could again operate the BRIGHT lamps. So I would use the BRIGHTS only momentarily to check for critters in the bar ditches of the two-lane rural road.
Did a search on the headlight dimmer switch and found only instrument panel dimmer (good stuff though) ... has anyone else had the headlight dimmer switch short with current/resistance? During the drive, I observed it was "all" headlamps being affected. I suspect that given the higher amperage of the BRIGHT lamps, the heat created a discontinuity in the switch itself.
I have yet to do any further trouble shooting, but thought I'd bounce it off the gurus here. Could this be as simple as a remove/replace the floorboard switch? Really hoping to avoid chasing (another) bad ground. Gotta love these old car and their original wiring harnesses!
Thanks.
with the BRIGHTS on for approx 10 minutes/so, the headlights started to fail ... I de-selected the BRIGHT and the low beam lamps operated continuously. After a few minutes of "cool down" I could again operate the BRIGHT lamps. So I would use the BRIGHTS only momentarily to check for critters in the bar ditches of the two-lane rural road.
Did a search on the headlight dimmer switch and found only instrument panel dimmer (good stuff though) ... has anyone else had the headlight dimmer switch short with current/resistance? During the drive, I observed it was "all" headlamps being affected. I suspect that given the higher amperage of the BRIGHT lamps, the heat created a discontinuity in the switch itself.
I have yet to do any further trouble shooting, but thought I'd bounce it off the gurus here. Could this be as simple as a remove/replace the floorboard switch? Really hoping to avoid chasing (another) bad ground. Gotta love these old car and their original wiring harnesses!
Thanks.
Burning Brakes
Joined: May 2013
Posts: 789
Likes: 129
From: Los Banos CA
When you say 'started to fail', do you mean that you lost all headlights? What was the exact symptom when they 'failed'? There is an 'automatic resetting' circuit breaker in the headlight switch that will cut out if the system starts drawing too much current. If that is the culprit, it could mean that the switch/circuit breaker is bad, or your headlights are just drawing slightly too much current.
Thread Starter
Racer
Joined: Aug 2018
Posts: 380
Likes: 170
From: Erath County Texas
When you say 'started to fail', do you mean that you lost all headlights? What was the exact symptom when they 'failed'? There is an 'automatic resetting' circuit breaker in the headlight switch that will cut out if the system starts drawing too much current. If that is the culprit, it could mean that the switch/circuit breaker is bad, or your headlights are just drawing slightly too much current.
When I depressed the floorboard dimmer switch to disengage the BRIGHTS, the low beam headlamps re-illuminated continuously. As I had a few miles to make and wanted to avoid an "abort" ... I used the low beams for most of the operation, selecting high beams/BRIGHTS only to check ahead for a minute or two, then switch back regardless of traffic/visibility condition. I have replaced the headlight switch "just because" in the last 2 years when I had the entire dash apart to remove/overhaul the speedo/odo/tach/vintage air install ... so I hope it's not the new switch in the dash. But I haven't changed the floorboard dimmer switch.
Hopefully that's not too difficult ... beyond the cramped quarters, of course. I'd like to re-wire it, but I can't do that right now. So I just carry a fire bottle! LOL.
Thanksf or the reply
Last edited by shaark92; Sep 23, 2020 at 10:29 AM.
Burning Brakes
Joined: May 2013
Posts: 789
Likes: 129
From: Los Banos CA
Replacing the floorboard dimmer switch should be fairly easy, so definitely try that first. I just looked at my wiring diagram, and both high and low beams do appear to go thru the beam selector switch (it could even be a bad connection at the selector switch). The switch is under the carpet in our 69, but later years mounted it over the carpet (not sure when the change was made, but our 79 has it over the carpet).
Thread Starter
Racer
Joined: Aug 2018
Posts: 380
Likes: 170
From: Erath County Texas
my 71 is under the carpet. When I first got the Vette 2 years ago, I was wondering about the dimmer cause I couldn't see the shiny round button down there like on my 61 Impala .... or Pop's 65 3/4 ton pickup.
thanks for checking your wiring diagram. I'm ordering one right now ... they're cheaper than the plastic bezel for the dash switch!!!! SMH.
that's interesting it went from above to below ... .and then back to above.
thanks for checking your wiring diagram. I'm ordering one right now ... they're cheaper than the plastic bezel for the dash switch!!!! SMH.
that's interesting it went from above to below ... .and then back to above.
Last edited by shaark92; Sep 23, 2020 at 10:56 AM.
Burning Brakes
Joined: May 2013
Posts: 789
Likes: 129
From: Los Banos CA
Thread Starter
Racer
Joined: Aug 2018
Posts: 380
Likes: 170
From: Erath County Texas
LOL ... sorry!
I'd say "if it works, roll on" .... but I think most of us Vette guys have a degree of OCD. IDK what the original on your 79 is, I guess it was early 80s when the switch went to the turn signal.
It's like when my buddy who's forgotten more about Vettes than I'll ever know ... currently has a 71 Warbonnet Yellow only 3 weeks older than Victoria ...commented on my ball cap, C3 logo. I didn't know there were multiple C3 badges ... turns out ... in fact ... the 71 has it's very own early C3. Your '69 checkered flag has a black checker at the top. Like my ball cap! The 71 has a WHITE checker at the top.
Then I discovered when it was repainted the original Ontario Orange, the fuel lid and the nose emblems ... yeah ... they're non '71 early C3. sigh. So much for my NCRS championship! LOL It DOES bother me I can't find a 71 C3 ball cap. The original horn button validates ... white square on top, not black.
I'd say "if it works, roll on" .... but I think most of us Vette guys have a degree of OCD. IDK what the original on your 79 is, I guess it was early 80s when the switch went to the turn signal.
It's like when my buddy who's forgotten more about Vettes than I'll ever know ... currently has a 71 Warbonnet Yellow only 3 weeks older than Victoria ...commented on my ball cap, C3 logo. I didn't know there were multiple C3 badges ... turns out ... in fact ... the 71 has it's very own early C3. Your '69 checkered flag has a black checker at the top. Like my ball cap! The 71 has a WHITE checker at the top.
Then I discovered when it was repainted the original Ontario Orange, the fuel lid and the nose emblems ... yeah ... they're non '71 early C3. sigh. So much for my NCRS championship! LOL It DOES bother me I can't find a 71 C3 ball cap. The original horn button validates ... white square on top, not black.
Pro
Joined: Apr 2012
Posts: 696
Likes: 193
From: USA
I have replaced the headlight switch "just because" in the last 2 years when I had the entire dash apart to remove/overhaul the speedo/odo/tach/vintage air install ... so I hope it's not the new switch in the dash. But I haven't changed the floorboard dimmer switch.
I had the same problem. Your new light switch is the problem. They are junk. They wont hold the amp the origional will. I replaced my light switch with a "new" one after the the dimmer resistor burned out. Low and behold the new switch did exactly what yours did.
I took my old switch apart and replaced the dimmer coil with the "new" one in order to have a working switch. Hopefully you still have your old one. I was able to undo the left side of the left dash and pry it rearward eough to replace the switch, difficult but doable without having to remove the steering column, et all.
I had the same problem. Your new light switch is the problem. They are junk. They wont hold the amp the origional will. I replaced my light switch with a "new" one after the the dimmer resistor burned out. Low and behold the new switch did exactly what yours did.
I took my old switch apart and replaced the dimmer coil with the "new" one in order to have a working switch. Hopefully you still have your old one. I was able to undo the left side of the left dash and pry it rearward eough to replace the switch, difficult but doable without having to remove the steering column, et all.
Last edited by CAMS69; Sep 23, 2020 at 11:53 AM. Reason: because
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Thread Starter
Racer
Joined: Aug 2018
Posts: 380
Likes: 170
From: Erath County Texas
I
I had the same problem. Your new light switch is the problem. They are junk. They wont hold the amp the origional will. I replaced my light switch with a "new" one after the the dimmer resistor burned out. Low and behold the new switch did exactly what yours did.
I took my old switch apart and replaced the dimmer coil with the "new" one in order to have a working switch. Hopefully you still have your old one. I was able to undo the left side of the left dash and pry it rearward eough to replace the switch, difficult but doable without having to remove the steering column, et all.
I had the same problem. Your new light switch is the problem. They are junk. They wont hold the amp the origional will. I replaced my light switch with a "new" one after the the dimmer resistor burned out. Low and behold the new switch did exactly what yours did.
I took my old switch apart and replaced the dimmer coil with the "new" one in order to have a working switch. Hopefully you still have your old one. I was able to undo the left side of the left dash and pry it rearward eough to replace the switch, difficult but doable without having to remove the steering column, et all.
I'm pretty sure the one I replaced was tossed. ughh. LED headlights to reduce the load???
that's an expensive change for something I rarely use.
thanks for the info!
Advanced
Joined: Dec 2017
Posts: 78
Likes: 18
From: Hawai'i, Island of Kaua'i
I had the same happen to mine when I rebuilt the lights, even before moving to LED's. The issue is the Amperage in the replacement headlight switch, as stated they are junk. The only way I found to remedy this was to wire the relays into the lights, effectively allowing the switch to run lower amperage and not having the issue. It also allows your original lights to be more reliable and brighter when being used. It's a relatively simple mod to do, that many other folks have documented on the forum. With a search you should be able to find the wiring guides and I was able to purchase the needed relays at the local auto parts store. Took an afternoon, but well worth the knowledge that the high amps aren't having to go all the way through the dash to turn on the headlamps.
Burning Brakes
Joined: May 2013
Posts: 789
Likes: 129
From: Los Banos CA
Melting Slicks
Joined: Feb 2017
Posts: 3,232
Likes: 1,232
From: PHX AZ
What are the headlights?????
When you say 'started to fail', do you mean that you lost all headlights? What was the exact symptom when they 'failed'? There is an 'automatic resetting' circuit breaker in the headlight switch that will cut out if the system starts drawing too much current. If that is the culprit, it could mean that the switch/circuit breaker is bad, or your headlights are just drawing slightly too much current.
Have you tried replacing the Headlights with CONVENTIONAL SEALED BEAMS? (and the 'problem goes away?)
With larger more powerful amp draw High beams....RELAYS to each light is in order!
Unkahal
Le Mans Master
Joined: May 2003
Posts: 8,875
Likes: 3,554
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
I had the same happen to mine when I rebuilt the lights, even before moving to LED's. The issue is the Amperage in the replacement headlight switch, as stated they are junk. The only way I found to remedy this was to wire the relays into the lights, effectively allowing the switch to run lower amperage and not having the issue. It also allows your original lights to be more reliable and brighter when being used. It's a relatively simple mod to do, that many other folks have documented on the forum. With a search you should be able to find the wiring guides and I was able to purchase the needed relays at the local auto parts store. Took an afternoon, but well worth the knowledge that the high amps aren't having to go all the way through the dash to turn on the headlamps.
EXACTLY Corey!!The replacement headlight switch built in circuit breaker are VERY problematic. Even stock headlights will still have a issue.
There are harness out there that are really nice ( read as expensive) and there are a few that are very affordable - stock lights it'll be fine.
And if you are so inclined you can make your own- the cheapest but it is time consuming-
Inexpensive option-
https://www.dapperlighting.com/colle...g-h4-relay-kit
Better-
https://www.danielsternlighting.com/.../products.html
Build you own-
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
This is the BEST solution. The original wiring "plan" will still work.....IF all the grounding connections are clean and well adjoined. But when they get tarnished, etc, the resistance in the (-) circuit increases and drags power from what is available for the lights. Current draw increases until the circuit breaker starts to trip.
This issue can be eliminated by installing relays as shown in prior post.
This issue can be eliminated by installing relays as shown in prior post.
Race Director
Joined: Nov 2006
Posts: 13,177
Likes: 7,781
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
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Cruise-In VIII Veteran
Just thought I'd chime in. About 20 years ago I thought it would be a great idea to install Halogen headlamps in my 77. At first I thought they were great! Nice bright headlights. Driving down a very dark road through the forests of northern Wisconsin one night on high beam. Lights just went out. Scary ****!
as you state above, would stay on on low beam. On High beam, all 4 lamps are lit. Just to much current for the headlight switch.
I wired in relays mounted on the left inside fender. Ran a power wire up from the starter Solenoid for clean power to the headlight relays. Switch and dimmer switch now just trigger the relays. Bright lights. Less load on aging wiring and switches.
as you state above, would stay on on low beam. On High beam, all 4 lamps are lit. Just to much current for the headlight switch.
I wired in relays mounted on the left inside fender. Ran a power wire up from the starter Solenoid for clean power to the headlight relays. Switch and dimmer switch now just trigger the relays. Bright lights. Less load on aging wiring and switches.
Last edited by 4-vettes; Sep 23, 2020 at 04:59 PM.
Le Mans Master
Joined: May 2003
Posts: 8,875
Likes: 3,554
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
This is the BEST solution. The original wiring "plan" will still work.....IF all the grounding connections are clean and well adjoined. But when they get tarnished, etc, the resistance in the (-) circuit increases and drags power from what is available for the lights. Current draw increases until the circuit breaker starts to trip.
This issue can be eliminated by installing relays as shown in prior post.
This issue can be eliminated by installing relays as shown in prior post.
I had one my bench- at 15A -the breaker would start clicking.
Race Director
Joined: Nov 2006
Posts: 13,177
Likes: 7,781
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
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Cruise-In VIII Veteran
It takes less than 1 amp to trigger a relay.
Burning Brakes
Joined: May 2013
Posts: 789
Likes: 129
From: Los Banos CA
And just in case you still aren't convinced that relays are the way to go..........I'd much rather do a relay conversion than tear the dash apart to replace the switch, especially since the replacement switch might end up doing the same thing. Plenty of people here have added relays (myself included), so you'll get plenty of help if you have questions. 
Le Mans Master
Joined: May 2003
Posts: 8,875
Likes: 3,554
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
SO- if you are stuck with a replacement light switch- you are best adding a relay harness..