LED Headlights: Turning on the fogs turns on the high beams, too!, New behavior, fogs worked normally until LED headlights installed. Options

[orthobiz]

I love my brand new GE Nighthawks. There is no way I could go back to regular headlights. I had a set of sealed beam Hellas.

Last night I turned on the fog lights for the first time and the high beams came on. When I looked at the front of the car, all three were on: the regular lights, high beams AND the fog lights.

Any fix for this? I would like to have the fog lights and the low beams on at the same time without the high beams.

Edit: up until I installed the LED headlights, turning on the fog lights did NOT turn on the high beams. And turning on the high beams turned OFF the fog lights. In other words, normal behavior.

Thanks,

Paul

[screenguy914]

Sounds like the PO switched wires on the headlight switch. Maybe someone has a cheat sheet showing wire color codes and their location. The factory wiring circuit helps some, but a photo would be best.

BTW, there are at least two different light switches on 914s. Specify the year and perhaps upload a pic of your light switch with connected wires.

Sherwood

[orthobiz]

Hopefully a pic soon, I have a 1974 1.8 liter. It had a single tone horn, plastic steering wheel, no center gauges. So it seemed like a car supplied without the appearance group originally. I bought it with chrome bumpers and fog lights that worked normally up until this latest upgrade. But entirely possible something weird was done if in fact the fogs were added after the fact.

Paul

[orthobiz]

I'm sure you meant more than this, but here's a picture of my switches:

(IMG:http://www.914world.com/bbs2/uploads_offsite/farm1.staticflickr.com-7438-1442536949.1.jpg)

[Mike Bellis]

In stock form, the highbeam circuit provides ground to the fog lamp relay coil only when the highbeams are off. It should be impossible for the fog lights to back feed this circuit as the power would need to jump across a terminal that never connects.

You will need to trace the wiring to figure it out.

[orthobiz]

Changed my topic heading to indicate that the fog lights used to work normally with the low beams only. The fog lights used to shut off when I turned on the high beams.

The only thing I changed was the headlights.

Thanks again,

Paul

[Chris Pincetich]

After installing my LED headlights, which coincided with other headlight wiring issues, my high beam relay is wonky. It always starts on high beam, which really flicker, then I click it once with a pull on the signal arm to get it to switch to low beams (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/blink.gif)

I need to get back under there and re-check all the wires and grounds! Good luck (IMG:style_emoticons/default/beerchug.gif)

[mepstein]

change it back. see if it fixes it's self.

[904svo]

Porsche used relay logic to operate the fog lamps, they used the low resistance of the high beam light to ground to the fog light relay. The fog lamp switch with supply battery to the other side of the relay to turn on the fog lamps when the high beams were turn on battery would be on both sides of the fog light relay this would cause it to release. I think with your arrangement you added relays for your new lighting system and the low resistance ground is now missing causing a feed back problem.

[orthobiz]

change it back. see if it fixes it's self.

My Golf R 2012 has LED headlights without fogs. I think the current setup even with the wonky high beams will be fine, I can live without the fogs I believe because these new LED headlights have such a great illumination right in front of the car.

I like 904svo's explanation. Must be something with the relays!

Paul

[orthobiz]

I am in no way an electrical genius BUT I've been thinking about the relay issue.

SO, I need a relay to switch between low and hi beams at the stalk.

BUT I don't need any relay to turn off the fog lights when I hit the hi beams. I'm an "on your honor kinda guy" so I'd turn the fogs off if I needed the hi beams. The automatic feature is not necessary for me.

SO, if there is a relay that automatically turns off the fog lights when I hit hi beams isn't there a way to bypass this function? Then, when I have the lo beams on and I turn on the fog lights somehow the hi beams will not be weirdly triggered on?

Where exactly is that relay and how could I "hardwire" the fog lights separate from the hi beam relay function?

Paul

[Dave_Darling]

There is no separate relay that cuts the fogs off. There is a relay that powers the fogs, and there is the high/low relay for the headlights. It's how they are wired together that provides the cutoff function.

Basic electrics: A relay is (more or less) an electrically-operated switch. The switch is spring-loaded so that by default, the #30 pin (usually the input for power) is connected to the #87a pin (most often not connected to anything). When power is connected to the #85 pin and the #86 pin is grounded, or vise versa, the magnet inside the relay pulls the switch so that #30 is connected to #87 (usually the output to power the light or whatever).

If #85 and #86 both have +12V, or both have ground, or either one is not connected, the spring in the relay keeps #30 connected to #87a.

Here are some pics of the guts of a relay:

(IMG:http://www.914world.com/bbs2/uploads_offsite/members.rennlist.com-121-1442682532.1.JPG) (IMG:http://www.914world.com/bbs2/uploads_offsite/members.rennlist.com-121-1442682533.2.JPG)



OK, so if you look for the stuff around relay J5, the foglight relay, tracks ~21-23 on this diagram: http://www.pelicanparts.com/914/parts/Elec...lectric_74B.jpg

OK, here is where it gets tricky. Pin 85 of the foglight relay is connected to the high beam circuit. (You can tell it's high beams because of the wire color, and because of the high beam indicator light K1 being connected to them.) Pin 86 of the relay is connected to the fog light switch, E7, and gets +12V when the switch is pulled. In order for the relay to close, and connect 30 to 87 and send power to the foglights, pin 85 has to be grounded.

It gets grounded through the high beam circuit of the left headlight, going through fuse #1 in the process. But, if power is going to the high beams, that part of the circuit will have +12V instead of being grounded. So both 85 and 86 will see +12V, no current will flow, so the relay will not switch on.

That's how the high-beam cutout is implemented.




So, how can changing the headlight effect that? The LEDs will have a different amount of resistance, for one thing. They also will not allow current to flow "backward" through them (they are diodes after all!) but I'm not sure that will have any effect here. I'm not sure what else off the top of my head.



OK, on to the high beams versus the low beams. You'll see that the high/low relay (J in the diagram) is kind of like a standard relay that loops back on itself. But the important part is that the input (pin 56) can only be connected to one output, either F or 56a. So if you are getting power to both the high and low beam circuits, power is getting to them in some other way.

The most probable cause, if this happened after changing the headlights, is that you have crossed up the wires on one or both lights. So double- and triple-check those connections, because it is very likely that you have one or more things swapped around.

--DD

[orthobiz]

Wow, incredible answer Dave! I'm gonna try to wade through it. All I seem to remember is V=IR from high school...

BTW, all I did was unplug the headlight connector from my old headlights and then I plugged the new headlights in.
It's a 3 prong connector and there is only one way it will fit in.

What I'd really like to do is uncouple the fog lights from the headlights. Which probably means disconnecting some kind of wire somewhere. Wiring diagrams are great but where are the specific relays located in the car? (I think under the dash)

Paul

[Dave_Darling]

The relays in question are located on top of the fuse panel. The high/low is a square box, the foglight relay is one of the regular round ones.

--DD

[Mike Bellis]

There is no way the fog lamp power circuit can effect the high or low beam power circuit. They are completely separate circuits.

The only connection is the high beam providing ground to the fog light relay when off and the headlight switch providing power when on.

The load side of these circuits are isolated. There must be some wiring messed up somewhere.

[steuspeed]

Then there is always the JWest fog light upgrade. Flash your fogs with all lights off. Also turn on fogs with lows/highs off. One of my favorite upgrades. Flash on coming classics or warnings for other drivers. Near dusk I drive with markers and fogs on so pop-ups are down. Running stock fogs and H4 high/lows. This mod is plug and play. You can go back to stock if desired.

http://www.jwesteng.com/shop/index.php?id_...troller=product

[Bartlett 914]

I believe on a stock car you don't want the fog and the high beams on at the same time due to excessive current draw. I assume the LED headlights draw less current eliminating this as an issue. You could them wire the fog relay to the fog switch as a separate circuit. I think removing and isolating the wire from 86 on the relay and grounding the relay connection 86 will do the trick.

[orthobiz]

I don't know the history of this car but it has no appearance group options except the fog lights so I assume it was added by a p.o.

I'll try to check into the fog relay. I wouldn't run the fogs and highs at the same time, I'd be "on my honor" on that one, it seems counterproductive anyway.

Someone musta crossed something somewhere!

Thanks again, everyone. I'll report back if I iron out this bug. I think the JWest relay might iron it out also...

Paul

[screenguy914]

Hi-Lo beams, headlight cover motor, running lights and fog lamps are all inter-connected at the light switch.

Attached are two views of the light switch from my '74.



Source voltage to the fog lamp switch is only activated when the headlight circuits and headlight doors are energized/ON.

As an aside, to operate the fog lamps independently, disconnect the fog source wire at the headlight switch and run a new source wire directly from the fuse box to the fog lamp switch. The switch energizes fog lamps via the fog lamp relay.

Hope this helps,
Sherwood

[john77]

Are you sure it doesn't already have the JWest fog light module? My car has it and I have the GE nighthawks too. Once I plugged the nighthawks in my lights started doing all sorts of crazy things. If I turn the fogs on the fogs don't come on but it switches the nighthawks to high beams. I just stopped using my fogs, and as soon as I get around to it I plan on removing the JWest module.