Fog light modification... Ideas?

[svxcess]

I will keep this simple. I would like to have the ability to have the fog light turn on independently of my normal headlights. I seems my 2 options are:

1. Run 12V through a relay and a separate switch to the fog lights and control it manually so I could have the fog lights work when the lights are totally off or just the parking lights are on.

2. Find out how to rewire or jump connectors so that my fog light switch could activate the lights when the light switch on the column stalk was in the parking lights position (as well as the normal headlight position) This is my preferred option.


Reasoning:

I do not know how the new HID system will operate in snowy weather from a standpoint of reflected glare from the snow back into my eyes or those of oncoming traffic. Since I drive quite a bit slower during these times, my need to see very far down the road with the headlights is decreased.

If I put H-3 HIDs into the fog lights (yes, they do exist) I may be able to use them as auxiliary headlights to still shine on the road adequately and not bother other drivers. I would turn these on with only the parking lights, leaving the main headlights off. They should be bright enough to adequately see, while also being bright enough to be seen by oncoming traffic.

Any thoughts from the electrical experts on how I would accomplish this modification and what wires to use? It seems like locating the parking light wire that connects to the headlight wire on the stalk and adding a splice to the parking light wire as well.

Something like a modified DRL system, but manually-controlled by the fog light switch and not automatically controlled by the ignition.


Am I making any sense here?

[ridered777]

Have a wiring diagram? My fog's don't work, and I've never taken the time to investigate, given my new HIDS... But this certainly sounds like a good idea.

I see your desire to run them to the parking lights - keeps them from being left on if all else fails, and your battery survives the catastrophe. On my previous car, I had fog's that would only work with the headlights activated, but altered them to work ALL the time. I just ran an 12v "jumper" wire to the power wire on it, and I was fine. I would assume that it would not be much more difficult on these cars, even if it was to run it to the parking light switch. You would just need a diagram, and my guess would be, that that circuit has and independent ground, all you have to do is splice the existing ground into that and you're good to go.

Trevor, correct me please.

[crazyhorse]

OK Here's what I've come up with. Taking power from the park light sw through the foglight sw to turn on a relay that turns on the bulbs. You STILL need a GOOD diagram to find the proper wires on the various switches. Then some simple wiretaps would suffice to run low current 12v to a relay.
Wiring it like my VERY CRUDE diagram would allow you to run them independently of the headlights.
First you'd need to unwire the foglight sw from the system, then run new wires, one from the tap in the parklight sw, the other to the relay. Then from the tap to the relay

I'm SURE Trevor will chime in to help, and correct me if need be.

[Trevor]

MY JDM car has the fog lights arranged such that they operate via a separate switch, which when turned on with the ignition on, brings on the fog lights together with the tail lights, but without the headlights. \

This would appear to be the only logical arrangement as one certainly does not want the headlights reflecting on fog, while the fog lights are set low to shine under the fog. Surely this is the object of having fog lights.

I would not wire the fogs such that they do not go off with the ignition. I have only days ago disconnected my parking lights as they tended to become accidentally left on, with a flat battery the result.

Sorry, but I must advise that your diagram is out of line. I could sort this out for you, but unfortunately I do not have a wiring diagram covering your car.

Head and fog lights are switched in the negative/ground circuit and include a relay for high beam. The circuitry is quite involved and incorporates blocking diodes in the indication light circuits. But do not let this deter you as separating the fogs should not be too difficult.

The approach will be to lift off the negative control circuit from the fogs and arrange things so that the existing switch provides a ground without the headlights being switched on. However I can not advise in detail without knowing how the existing system is arranged.

[crazyhorse]

Originally Posted by Trevor

Sorry, but I must advise that your diagram is out of line. I could sort this out for you, but unfortunately I do not have a wiring diagram covering your car.

That's why I'm here, to learn

[Crazy_pilot]

My fog lights act as daytime running lights. That is, they are on during the day when the headlights are off. When I turn the headlights on the fogs turn off and are controlled by the dash switch.

[huck369]

The Impreza crowd have covered this....though I'm not completely familiar with the mod, it basically requires changing the power source to the fog light switch, so that it has power any time the ignition is on, instead of feeding off the low beams power source.....
basically a one wire change.

[Trevor]

Originally Posted by huck369

The Impreza crowd have covered this....though I'm not completely familiar with the mod, it basically requires changing the power source to the fog light switch, so that it has power any time the ignition is on, instead of feeding off the low beams power source.....
basically a one wire change.

This makes sense, provided that the switch is in the B+ supply line and is not in the ground circuit in accordance with the headlight circuitry.

In the event that the ground is switched, it will be the B+ line to the fog lamps which will require changing to an ignition on supply point.

Surely someone with a wiring diagram can sort this out. Strangely my JDM diagram does not show the fog lamp circuit in any shape or form.

[Hocrest]

Over on one of the Legacy forums there is a detailed post on doing this. I'll post a link when I get home.

[svxistentialist]

My JDM ones were like Trevor's. And it seems sensible for use.

The UK ones have different lamps, with no bulb in the fog position, nor any switch to use either.

Joe

[PaulDexler]

Trevor and Joe, the way the fog lights work on your cars is the way they should work, that is if it were up to engineers and not politicians. Unfortunately, in most of the States, particularly here in California, it is illegal (!) to have the fog lights on without the low beam headlights. Nobody is going to stop you for it, but if they stop you for some other reason and then do a "safety check" and find it, you have to change it back and get it signed off. Bah!Humbug! Lawmakers should stop trying to be automotive engineers!
It should be possible to wire the dash switch to turn on the fog lights no matter what position the headlight switch is in. Better yet, wire the fogs up to the parking light circuit (not the switch on top of the column, but the first click of the light switch.) That way when you turn off the lights with the main switch, everything gets shut off.

[Hocrest]

Originally Posted by Hocrest

Over on one of the Legacy forums there is a detailed post on doing this. I'll post a link when I get home.

Here's the thread from SLI. Of course the details are different, but it may give some ideas???

[svxistentialist]

Originally Posted by PaulDexler

Trevor and Joe, the way the fog lights work on your cars is the way they should work, that is if it were up to engineers and not politicians. Unfortunately, in most of the States, particularly here in California, it is illegal (!) to have the fog lights on without the low beam headlights. Nobody is going to stop you for it, but if they stop you for some other reason and then do a "safety check" and find it, you have to change it back and get it signed off. Bah!Humbug! Lawmakers should stop trying to be automotive engineers!
It should be possible to wire the dash switch to turn on the fog lights no matter what position the headlight switch is in. Better yet, wire the fogs up to the parking light circuit (not the switch on top of the column, but the first click of the light switch.) That way when you turn off the lights with the main switch, everything gets shut off.

Paul, when I ran the JDM car, I used to use them a lot with the sidelights, I suppose in low light situations, and they would have filled the function of what you guys call DRLs.

Also, they were exceptionally useful if driving a country lane at night in the rain, if switched on they lit up the road and kerb near the car, so you could spot potholes and potential hazards. In this use mode they stayed on whether you used main or dipped lights.

The only bother they caused was from other drivers. If you had them on with the mains, you had 3 lamps lit in a row. Other drivers tended to flash for this, they "saw" or interpreted the inner set as driving lamps, long range spotlamps.

This was actually a ridiculous interpretation, as I said above, they only lit up the road near the car, they did not shine long range and so could not dazzle. However, fog lamps here are traditionally below the bumper. Anything seen above bumper level is presumed to be a spotlight or long range lamp.

The law here in Ireland stipulates that fog lamps should not work with main beams. I have never been pulled for it, but that law is in place.

Joe

[svxcess]

Since I have the honor of having the first set of 5000K HIDs from svxfiles on the road (and loving every freakin' lumen), it seems only appropriate that i also have the first set of 5000K HID foglights (H3). A little wiring modification at the bulb end and parallel ballasts and I am good to go.

Tom is ordering them for me and hopefully by the time I am ready to install them the end of October, this wiring thing will be worked out, or shortly thereafter.

As long as its in place by our first snowfall. Since I have no parking lights in my front corners, only turn signals (UK-spec) it may look funny with just two small (but incredibly bright bulbs) up front.

And on those snowy, back country roads at night,with no traffic, just another click of the headlight switch and its suddenly noon!

,

[Trevor]

Originally Posted by svxcess

I will keep this simple. I would like to have the ability to have the fog light turn on independently of my normal headlights. :

Firstly, I thank you sincerely for posting to me, at considerable expense, a copy of the US Electrical Manual. With this on hand I have been able to sort out what is rather a convoluted method of achieving a rather simple outcome. The brand of logic, the automotive electrical profession uses is incredible.

The existing fog light switching is interlocked in two ways via the fog lamp relay. Firstly in the negative/ground leg, via the dimmer switch, such that this must be in the dim/low position. Secondly by using a B+ supply to the fog lights, via the left hand head light relay, such that this must be energised, i.e. the head lights switched on.

The fog light relay is energised via terminal MB3 and 15 amp fuse, 24 when the fog light switch is closed, but only provided the headlamp relay is activated. This is the circuit which must be altered so that supply is not dependent on the head light circuit.

All things considered, the deciding factor will be accessibility. My problem is that I do not have a US left hand drive car to tinker with, so that I will have leave the physical aspects still to be sorted out.

A red coded conductor runs from terminal (1) on fog relay connector F2, to main fuse board terminal MB3. The question is as to whether this is a separate lead which can be removed at MB3, or is there a junction made within the loom? The wiring diagram is not exact in this regard, but considering the location of the components involved, I would expect there to be a separate lead.

If so, this lead should be coloured red and as only relay current is involved, the conductor should have a relatively small cross section. When disconnected the fog lamps when illuminated should extinguish, and this should provide a means of identification. The object will be to disconnect the lead and connect it constant point of supply e.g. terminal MB6, (i.e. Switch the lead from MB3 to MB6).

An alternative would be to make alterations at the fog lamp relay, situated under the dash panel. Here the same red lead connects to pin (1) and should be disconnected. Pin (1) must then be provided with an alternative supply from a nearby source.

If a permanent supply is used as per the most convenient connection points as above, there is a problem to consider. It is best that the fog lights are dependent on the ignition being on, otherwise they could be inadvertently left on, resulting in a flat battery. I have experienced this as a result of leaving side parking lights on.

Therefore it would be wise to pick up a supply from a point switched via the ignition, either accessory position, or ‘on’ position. Fuse board terminals FB10, 15 amp fuse 2, and FB17 20, amp fuse 3 are shown as empty and either could provide the required supply point.

A second and possibly an easier alternative, if a constant supply to the relay is used, would be to change the existing constant B+ supply to the fog lights to an ignition accessory switched source. This could be done by moving the red/yellow lead on connection FB41, 15 amp fuse 4, to FB10 or FB17.

I have tried to keep my explanation as concise and simple as possible, but without detail the requirements would be difficult to exactly understand. Explanations of this sort are not easy to transfer as text. Any attempt to rehash the drawings from the manual would be futile. Proper schematics are the answer. Not bastardized, half cock wiring diagrams.