SOLVED- LED Headlights creating issue with fog lights, '71 Factory 914-6 NOS Harness Options

[Cairo94507]

So we installed the GE Nighthawk LED headlights on my car. We then hooked up the fog lights and we get headlights that flicker the low beam when we turn on the fog lights. We switched to the typical H4 headlights and everything works as it should. So I know this has been discussed. Has anyone solved this problem?

I want to have my fogs wired so I can have them on with low or high beam or have just my fog lights on, kind of as a DRL with no headlights on. This is a stock '71 914-6 with an NOS '71 914-6 harness. So no prior monkey business with the wiring.

Your thoughts and expertise are welcome.
Cheers,
Michael

[FlacaProductions]

http://www.914world.com/bbs2/index.php?sho...=264737&hl=
Big thread here.
The "ground the blue/white wire" described on page 4 did the trick for me...

[Cairo94507]

FlacaProductions - In speaking with Bob, he believes that will solve this issue. Thanks very much for responding to my post. (IMG:style_emoticons/default/beerchug.gif)

[mepstein]

If you continue to have trouble, just ring up Spoke/Jerry. He's pretty amazing with this stuff.

[Cairo94507]

Thanks - I will keep that up my sleeve and hope we do not need to bother Jerry. Thanks, Michael

[lierofox]

Thanks - I will keep that up my sleeve and hope we do not need to bother Jerry. Thanks, Michael

In the stock wiring on a 914, the ground side of the relay coil for the fog lights connects to the hot side of the high beam filament on the headlights.

The current through the relay coil is so small that it doesn't even warm up the high beam filament so it doesn't glow, it just acts as a nice, convenient path to ground, but when you turn the high beams on, it sends 12v to that wire, causing the convenient path to ground to disappear for the relay since the filament warms up.

This is what causes the fog lights to turn off automatically when you switch the high beams on.

With LED headlights, they don't function the same way at all, my guess is that the small amount of power trying to flow through the fog light relay is probably triggering the headlight's circuitry into thinking "Oh, I see 12V on the high beam terminal, time to switch to the high beam LED and turn off the low beam!" attempting to switch to high beams, not getting enough power on the wire for it (since it's just being fed through the high resistance tiny coil of the relay and is only a few milliamps of current) and then resetting and going right back to turning on the low beams again, causing the flicker.

So when switching to LED headlights there's a couple options that come to mind.

Option 1, you can add a high power ballast resistor between the high beam wire and ground, this basically removes the benefits of LED headlights though, adds current draw, makes heat, and might not even help the flickering low beam in your case.

Option 2, you can move the ground for the fog light relay from the high beam circuit, and instead ground it out to the chassis, in which case the fog lights can be turned on regardless of if you have high or low beams on.

(If you want to RETAIN that auto-off feature, option 2 can be modified by having power for the fog lights be fed through an additional relay, but using the normally closed contacts, this relay is actuated using the high beam wires so when the high beams are on, the contacts open and power is cut to the fog light system. (This adds an extra relay that may need replacement/servicing down the road.))

For your particular situation though, since you want to have your fog lights on even if the headlights are off, you'll want to move 2 wires, one on the fog light relay, one on the fog light switch.

First, move the white/blue wire on the fog light relay to a chassis ground, this is the same as the post FlacaProductions linked to, and will remove the interaction between the fog lights and the high beams, and then you'll also have to move the Brown/Blue wire on the fog light switch to a fuse that gets power with the key on, possibly the blower motor fuse, or the brake light fuse, which should be fuses 8 and 9 respectively (but I'm not 100% on the 914-6's fuse box arrangement.) This will allow you to turn the fog lights on even with the headlights off.

[Cairo94507]

Lierofox - Thank you. I have forwarded your information to The Justice League. (IMG:style_emoticons/default/beerchug.gif)

[lierofox]

Lierofox - Thank you. I have forwarded your information to The Justice League. (IMG:style_emoticons/default/beerchug.gif)

We'll see how Aqua Man handles this. Hopefully he doesn't try throwing a shark at it.

Again.

[Cairo94507]

(IMG:style_emoticons/default/av-943.gif) I hope not. I like sharks. (IMG:style_emoticons/default/beerchug.gif)

[Cairo94507]

OK- problem solved thanks to the info posted above by FlacaProductions and lierofox. Thank you guys. (IMG:style_emoticons/default/beerchug.gif)

[Dave_Darling]

What's fun is that you can hook up a permanently-powered wire instead of the switched-power wire and use the fog lights even when the engine is off! Then drive your GF out on a date to see a show, and forget that you turned the lights on. So when you come back to the car, it is dead as a doornail.

Always fun to wait for AAA at midnight in SF.... :eyeroll:

--DD

[mepstein]

What's fun is that you can hook up a permanently-powered wire instead of the switched-power wire and use the fog lights even when the engine is off! Then drive your GF out on a date to see a show, and forget that you turned the lights on. So when you come back to the car, it is dead as a doornail.

Always fun to wait for AAA at midnight in SF.... :eyeroll:

--DD

The knob on my fog lights up so that's not usually an issue for me. I have left a turn signal on and killed the battery.

[Cairo94507]

Yeah, my fog light switch lights up as stock. Should be fine. (IMG:style_emoticons/default/beerchug.gif)

[FlacaProductions]

OK- problem solved thanks to the info posted above by FlacaProductions and lierofox. Thank you guys. (IMG:style_emoticons/default/beerchug.gif)

OMG this makes me so happy. I haven't been on this board very long but had this same issue and resolved it with the help here - so when I saw the question, I was like Horshack in the back of Kotter's class with his hand waving furiously....Oooh Oooh Oooh!

[Luke M]

So we installed the GE Nighthawk LED headlights on my car. We then hooked up the fog lights and we get headlights that flicker the low beam when we turn on the fog lights. We switched to the typical H4 headlights and everything works as it should. So I know this has been discussed. Has anyone solved this problem?

I want to have my fogs wired so I can have them on with low or high beam or have just my fog lights on, kind of as a DRL with no headlights on. This is a stock '71 914-6 with an NOS '71 914-6 harness. So no prior monkey business with the wiring.

Your thoughts and expertise are welcome.
Cheers,
Michael

Hi Michael,

Which one of the listed "fixes" did you guys end up using?
Is this a problem with just the GE led nighthawks or all led headlights ?
Also did you see this thread. It may or may not interest you :

http://www.914world.com/bbs2/index.php?showtopic=330111

I have Kroon building me a new 6 chassis wire harness and wonder if I should ask to make any changes to it now. I would rather not cut into my new harness to modify it.
Also thinking of having Kroon add 4 extra spare wires from the dash to engine bay.

[Cairo94507]

Good Morning Luke M - I am not sure which way Bob went to make this work for me. Hopefully he will chime in.

As for your harness, I like the idea of adding some extra wires from the engine up to the dash. I would also think about a 3rd brake light. For my car I asked the guys to add one in the most invisible way possible and I look forward to seeing it. I also wanted to have the front turn signals wired for the european front signals with the white portion on with the lights and the amber for turn signals only. Additionally, I wanted to have the warts on with the parking lights and then toggle-flash with the turn signal for some side lighting when turning.

Do I sound like I am afraid my car will get hit by some ignorant, careless 16-year-old wearing a baseball cap with a hoodie covering it, ear buds in and his phone in his hand as he texts while he drives....yeah I am very afraid of that. Kids where I live drive 400 HP cars like maniacs and crash them all of the time. I always pray they crash solo into a tree, concrete pillar or something. Sadly, they often hit the innocent person who is just going to work, grocery store, etc. (IMG:style_emoticons/default/slap.gif)