Headlight Problem m- Can you help
Thread Starter
Racer
Joined: Nov 2012
Posts: 367
Likes: 16
From: London
Headlight Problem - Can you help
C3 1970 Convertible 454
My car has been off the road for a few years during a restoration. New engine bay wiring loom fitted from leading supplier (all connections were swapped out as I worked my way round the old loom so all wires are connected) and all the lights and electrics are working fine apart from the headlamps that do not light up (marker lamp, turn indicators and parking lights are fine), When I step on the high beam switch in the footwell the high beam indicator on the dash lights up so power to that point, however nothing at the head lights.
Although on separate circuit I also noticed the horns are not working, but I think as I restored and repainted these this is probably an earthing problem.
Before I start to investigate further any ideas welcome.
Stay safe and well
Kind regards
Paul
My car has been off the road for a few years during a restoration. New engine bay wiring loom fitted from leading supplier (all connections were swapped out as I worked my way round the old loom so all wires are connected) and all the lights and electrics are working fine apart from the headlamps that do not light up (marker lamp, turn indicators and parking lights are fine), When I step on the high beam switch in the footwell the high beam indicator on the dash lights up so power to that point, however nothing at the head lights.
Although on separate circuit I also noticed the horns are not working, but I think as I restored and repainted these this is probably an earthing problem.
Before I start to investigate further any ideas welcome.
Stay safe and well
Kind regards
Paul
Last edited by PBCloud; Jan 18, 2021 at 11:33 AM.
Melting Slicks
Joined: Feb 2018
Posts: 2,326
Likes: 721
From: Marietta GA
You may have a ground problem on the circuit going to the head lights. Look on this site to download a wiring schematic for a 1970 model. With the wiring schematic you can rig a temporary ground (earthing) to see if that is your problem. I don’t recall any association between the horn and the headlights. Be sure and check the large multi wire plug going to the dash panel headlight switch. I put mine on wrong and lost all of my dash lights. It’s a pain to get access to the switch, that is why I would try it after everything else checks out. There have been posts about restoration switches being bad out of the box. If you have a voltage meter it would be wise to see if there is 12 volts present at the headlight plugs. Good Luck, let us know what you find.
Racer
Joined: Jan 2017
Posts: 271
Likes: 120
From: Rock Hill South Carolina
Agree with the ground suggestion- but if parking and turn lights work that tends to argue against that since (I think) they share the same ground point. Definitely get the wiring diagram to verify how everything is grounded.
Since you have functionality in the dash, and since it’s the engine harness that’s swapped I’d check for power at the firewall on both headlight and high beam wires. If you have power there, then the problem is forward.
good luck!
steve
Since you have functionality in the dash, and since it’s the engine harness that’s swapped I’d check for power at the firewall on both headlight and high beam wires. If you have power there, then the problem is forward.
good luck!
steve
Le Mans Master
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Thread Starter
Racer
Joined: Nov 2012
Posts: 367
Likes: 16
From: London
Wow! thanks for such quick and comprehensive replies, this will shorten my investigation when I will use a circuit checker in the next few days. I will let you know what I find.
Where it mentions in the help list above that the circuit breaker is in the headlight switch, does it refer to the dimmer switch and is this part of the switch itself or in one of the wires before or after the switch?
Kind regards
Paul
Where it mentions in the help list above that the circuit breaker is in the headlight switch, does it refer to the dimmer switch and is this part of the switch itself or in one of the wires before or after the switch?
Kind regards
Paul
Le Mans Master
Joined: May 2003
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From: Fernandina Beach FL
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Wow! thanks for such quick and comprehensive replies, this will shorten my investigation when I will use a circuit checker in the next few days. I will let you know what I find.
Where it mentions in the help list above that the circuit breaker is in the headlight switch, does it refer to the dimmer switch and is this part of the switch itself or in one of the wires before or after the switch?
Kind regards
Paul
Where it mentions in the help list above that the circuit breaker is in the headlight switch, does it refer to the dimmer switch and is this part of the switch itself or in one of the wires before or after the switch?
Kind regards
Paul
I'd check for power at the headlights-could be a combo of bad bulbs and connections there.
Thread Starter
Racer
Joined: Nov 2012
Posts: 367
Likes: 16
From: London
Thanks Richard
Yes the high beam is lighting up in the speedo when the switch in the footwell is pushed. That's really useful guidance and I will have a hunt around with my circuit tester at the headlamp end first.
As I completely dismantled, rebuilt and repainted both the pop-ups I suspect its a loose connection somewhere.
Keep safe and well
Kind regards
Paul
Yes the high beam is lighting up in the speedo when the switch in the footwell is pushed. That's really useful guidance and I will have a hunt around with my circuit tester at the headlamp end first.
As I completely dismantled, rebuilt and repainted both the pop-ups I suspect its a loose connection somewhere.
Keep safe and well
Kind regards
Paul
Last edited by PBCloud; Jan 19, 2021 at 03:46 AM.
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start at the headlights and check for power and check the grounds, then work towards the switches.
Highway Man
Joined: Apr 2019
Posts: 445
Likes: 188
From: Ca
I'm seeing another thread opened by you with several members giving you advice on this same issue?
https://www.corvetteforum.com/forums...970-454-a.html
https://www.corvetteforum.com/forums...970-454-a.html
Thread Starter
Racer
Joined: Nov 2012
Posts: 367
Likes: 16
From: London
Hi Guys
As it was a slightly different issue started a new thread, in that previous one we were discussing the same problem of no headlamps, whilst the markers, indicators and parking lights were all ok and how to trace the fault. Based on you responses I am trying to track the problem back from the headlights which seemed to make the most sense.
I found using my circuit tester that I then ran into this issue as I have power at the high beam switch but none at the headlamps, so assume the problem must be somewhere in between. I can see where the green blue and brown (tan) wires that connect to the high beam switch disappear into the bulkhead behind the fuse box in the footwell on the driver side but could not track them coming out of the bulkhead on the engine side, yet guidance I found was that the wiring goes direct to the headlights, so without being being to find a separate direct wire assumed it connected to the fuse box somewhere and hence then feeds into the harness through the plug connector to emerge from near the headlamps. This is what I was trying to confirm before I go hunting again with my circuit tester i.e. is this last assumption correct.
Kind regards
Paul
As it was a slightly different issue started a new thread, in that previous one we were discussing the same problem of no headlamps, whilst the markers, indicators and parking lights were all ok and how to trace the fault. Based on you responses I am trying to track the problem back from the headlights which seemed to make the most sense.
I found using my circuit tester that I then ran into this issue as I have power at the high beam switch but none at the headlamps, so assume the problem must be somewhere in between. I can see where the green blue and brown (tan) wires that connect to the high beam switch disappear into the bulkhead behind the fuse box in the footwell on the driver side but could not track them coming out of the bulkhead on the engine side, yet guidance I found was that the wiring goes direct to the headlights, so without being being to find a separate direct wire assumed it connected to the fuse box somewhere and hence then feeds into the harness through the plug connector to emerge from near the headlamps. This is what I was trying to confirm before I go hunting again with my circuit tester i.e. is this last assumption correct.
Kind regards
Paul
Thread Starter
Racer
Joined: Nov 2012
Posts: 367
Likes: 16
From: London
Problem solved!!
Well guys I guess its a case of try the basics first!..........as it was difficult to get to I assumed incorrectly I had connected the firewall plug on the new engine and lighting harness properly, after all all I fitted them when the engine was out with easy access so I must have got his right!!!
How wrong could I be, as I could not find any circuit faults I finally went to the plug. What I had not realised was that whilst I had firmly pushed this all the way in and the centre bolt tightened was tightened to what I felt was firm (did not want to risk overdoing this in case I damaged the 50 year old firewall socket), it turned out it was not fully located and all I needed to do was tighten the centre bolt down to pull the plug into the firewall socket (some thing I did not realise was that it snugly fits into a recess rather then stays flush).
So annoying as I spent so much time hunting this problem down, but I guess the bonus is now I really know the wiring circuits and connections really well as I just about traced and tested them all, so I guess that will always be useful going forward.
Many thanks for all your patience, diagrams, pictures and help.
A tip I picked up from a Google search was that access and sight of the firewall plug whilst awkward from under the car (which put me off checking this for a while) it is quite easy by removing the side air vent (1970 car) , just don't know why I did not think of this and using a mirror to inspect the contacts etc. makes life much easier.
Keep safe and well
Kind regards
Paul
Well guys I guess its a case of try the basics first!..........as it was difficult to get to I assumed incorrectly I had connected the firewall plug on the new engine and lighting harness properly, after all all I fitted them when the engine was out with easy access so I must have got his right!!!
How wrong could I be, as I could not find any circuit faults I finally went to the plug. What I had not realised was that whilst I had firmly pushed this all the way in and the centre bolt tightened was tightened to what I felt was firm (did not want to risk overdoing this in case I damaged the 50 year old firewall socket), it turned out it was not fully located and all I needed to do was tighten the centre bolt down to pull the plug into the firewall socket (some thing I did not realise was that it snugly fits into a recess rather then stays flush).
So annoying as I spent so much time hunting this problem down, but I guess the bonus is now I really know the wiring circuits and connections really well as I just about traced and tested them all, so I guess that will always be useful going forward.
Many thanks for all your patience, diagrams, pictures and help.
A tip I picked up from a Google search was that access and sight of the firewall plug whilst awkward from under the car (which put me off checking this for a while) it is quite easy by removing the side air vent (1970 car) , just don't know why I did not think of this and using a mirror to inspect the contacts etc. makes life much easier.
Keep safe and well
Kind regards
Paul