LED Headlights
Race Director
Joined: Mar 1999
Posts: 12,584
Likes: 237
From: Bartlett Illinois
EDIT: I do know that if the parking lights are on only with the fogs one the headlight will be dim, it is not that, but dim when switched to headlights.
It could be a simple as the harness connection
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
I think it has something to do with the ionization of the gas in the bulb. I read somewhere that HIDs are not legal as headlights because they can't be "flashed" at oncoming motorists.
Race Director
Joined: Mar 1999
Posts: 12,584
Likes: 237
From: Bartlett Illinois
My HIDs do that. It takes about 10 or 15 seconds for them to come up to full brightness when they are cold.
I think it has something to do with the ionization of the gas in the bulb. I read somewhere that HIDs are not legal as headlights because they can't be "flashed" at oncoming motorists.
I think it has something to do with the ionization of the gas in the bulb. I read somewhere that HIDs are not legal as headlights because they can't be "flashed" at oncoming motorists.
Pro
Joined: Oct 2012
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Likes: 120
From: Grapevine TX
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Pro
Joined: Sep 2008
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From: St James New York
Agreed 100%. I'm going to do the relay harness just to fix the foglight issue. I'd rather do that than start hacking up the stock wiring in the hopes of fixing it without knowing for certain what will work and what won't.
No need to hack into anything, what we need to do is find where to run an independent ground for the fogs. If we could do that from a relay it would mean inserting one black 16 gauge ground wire into the relay contact and running it to a suitable grounding point. Very simple and easy, no hacking required and could be easily removed without a trace!
On my 96 I understand the headlight relay is under the dash on the passenger side, not sure if the 89 relay is in the same position. Regardless, I think that method would still entail cutting the stock wiring harness and then running a ground to the relay. I like the idea of the plug-and-play relay harness much better than the thought of cutting my stock wiring.
No need to hack into anything, what we need to do is find where to run an independent ground for the fogs. If we could do that from a relay it would mean inserting one black 16 gauge ground wire into the relay contact and running it to a suitable grounding point. Very simple and easy, no hacking required and could be easily removed without a trace!
On my 96 I understand the headlight relay is under the dash on the passenger side, not sure if the 89 relay is in the same position. Regardless, I think that method would still entail cutting the stock wiring harness and then running a ground to the relay. I like the idea of the plug-and-play relay harness much better than the thought of cutting my stock wiring.
Why, I don't get it....... do you know how much work that is, if you install it correctly and make it look OEM with the correct corrugated wire loom, tied off and tucked away properly. That's even if you can find a manufacturer that makes an aftermarket headlight harness for a C4! Do you even know who makes one that will fit a C4's dimensions?
Have you ever done something like that on a vehicle? I have, on a Jeep, and it took me hours but looked completely factory and worked great when I was done. I needed the extra juice it provided while running high wattage halogen bulbs. A new independent headlight wiring harness is not needed or required to ground the OEM fogs with LED headlights.
It's like replacing your rotors, pads and brake lines when all you really need to do is bleed the fluid in them!
Last edited by mako41; Dec 1, 2014 at 04:49 PM.
Pro
Joined: Oct 2012
Posts: 579
Likes: 120
From: Grapevine TX
In my case it's a matter of Patrick has given us a solution that will definitely work and the schematics for the harness don't look all that difficult to make. I haven't looked at the stock headlight relay because it's a bit of a pain to get to but I presume it plugs into a harness plug that would mean you can't simply pull a connector wire from the ground contact and replace it with a separate wire. If someone has done that and can give specific instruction I'd be happy to try it but I'm no electrical expert so I'm loath to start tinkering blindly. As for grounding the foglights separately, that's the first thing I thought of on my own. I believe it would be fairly easy to do but the probability that it would cause the blue high beam indicator to light whenever the fogs are on is enough to keep me from going that route.
Melting Slicks
Joined: Jul 2011
Posts: 2,605
Likes: 202
From: Trinity FL
No, you are not making an entire new harness. Its extremely simple. I am not a master electrician, nor can I read schematics very well. When I ran HID headlights and Fogs I built a new harness with two relays one for low, one for high, and an inline fuse. This allowed my fogs to work again since an HID bixenon bulb has no filament. Took me an hour....not very hard. The harness tucks right up next to your existing harness.
Still don't see the issue here lol...there is more than one way to skin a cat though. If you want to splice and cut into original factory wiring go for it man lol. Just providing a simple solution. If it takes you more than 2 hours to build and install a harness once you have all the compoments laid out then you might have more serious problems to worry about...Especially if you have been reading and researching how to make it before all the pieces arrive.
For what its worth, the putco harness off amazon will work perfectly but you may need to extend the positive lead and the relays probably aren't as solid as waterproof hella relays.
Still don't see the issue here lol...there is more than one way to skin a cat though. If you want to splice and cut into original factory wiring go for it man lol. Just providing a simple solution. If it takes you more than 2 hours to build and install a harness once you have all the compoments laid out then you might have more serious problems to worry about...Especially if you have been reading and researching how to make it before all the pieces arrive.
For what its worth, the putco harness off amazon will work perfectly but you may need to extend the positive lead and the relays probably aren't as solid as waterproof hella relays.
You would prefer to run an entire new headlight harness?
Why, I don't get it....... do you know how much work that is, if you install it correctly and make it look OEM with the correct corrugated wire loom, tied off and tucked away properly. That's even if you can find a manufacturer that makes an aftermarket headlight harness for a C4! Do you even know who makes one that will fit a C4's dimensions?
Have you ever done something like that on a vehicle? I have, on a Jeep, and it took me hours but looked completely factory and worked great when I was done. I needed the extra juice it provided while running high wattage halogen bulbs. A new independent headlight wiring harness is not needed or required to ground the OEM fogs with LED headlights.
It's like replacing your rotors, pads and brake lines when all you really need to do is bleed the fluid in them!
Why, I don't get it....... do you know how much work that is, if you install it correctly and make it look OEM with the correct corrugated wire loom, tied off and tucked away properly. That's even if you can find a manufacturer that makes an aftermarket headlight harness for a C4! Do you even know who makes one that will fit a C4's dimensions?
Have you ever done something like that on a vehicle? I have, on a Jeep, and it took me hours but looked completely factory and worked great when I was done. I needed the extra juice it provided while running high wattage halogen bulbs. A new independent headlight wiring harness is not needed or required to ground the OEM fogs with LED headlights.
It's like replacing your rotors, pads and brake lines when all you really need to do is bleed the fluid in them!
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
In my case it's a matter of Patrick has given us a solution that will definitely work and the schematics for the harness don't look all that difficult to make. I haven't looked at the stock headlight relay because it's a bit of a pain to get to but I presume it plugs into a harness plug that would mean you can't simply pull a connector wire from the ground contact and replace it with a separate wire. If someone has done that and can give specific instruction I'd be happy to try it but I'm no electrical expert so I'm loath to start tinkering blindly. As for grounding the foglights separately, that's the first thing I thought of on my own. I believe it would be fairly easy to do but the probability that it would cause the blue high beam indicator to light whenever the fogs are on is enough to keep me from going that route.
Are you sure you know how to make that work?? Did the guy recommending this solution actually do this on an LED equipped 'vette and get the desired result?
I'll find a way to ground the OEM fogs to work with the LED headlights and the OEM switches and when I do I'll clue you in!
Pro
Joined: Oct 2012
Posts: 579
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From: Grapevine TX
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
I see everyone laughing but I still fail to see the need to run a redundant wiring harness just to ground the fogs!
Time, expense & effort, wasted when all you need to do is find a way to ground the fogs while bypassing the OEM headlight wiring design that doesn't allow the fogs and hi-beams to work together. The issue is that GM designed our 'vetts to not allow the fogs and hi beams to run at the same time. Finding the relay or related wiring that do this will go a long way into finding a solution to this problem.
When I do things I do them right and they look OEM, that takes time and effort boys and I never hack into OEM harness' to make my projects work, ever! When I figure out a grounding solution that works with the LED's I'll let you all know.
Have a nice day!
Time, expense & effort, wasted when all you need to do is find a way to ground the fogs while bypassing the OEM headlight wiring design that doesn't allow the fogs and hi-beams to work together. The issue is that GM designed our 'vetts to not allow the fogs and hi beams to run at the same time. Finding the relay or related wiring that do this will go a long way into finding a solution to this problem.
When I do things I do them right and they look OEM, that takes time and effort boys and I never hack into OEM harness' to make my projects work, ever! When I figure out a grounding solution that works with the LED's I'll let you all know.
Have a nice day!
Last edited by mako41; Dec 2, 2014 at 07:24 PM.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Race Director
Joined: Mar 1999
Posts: 12,584
Likes: 237
From: Bartlett Illinois
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
It looks like it may be possible to run an independent ground for the fogs from the light green wire(s) at the S126 node?? I'll have to investigate further, not really sure how that would effect the hi-beam indicator on the instrument panel. It seems that the fogs are grounded thru the passenger side headlamp. With LED's instead of the OEM halogen headlamp there is no path to ground for the fogs to power up.
