Stock Fog Re-wire?

bg478 · 11-19-2004, 10:15 AM

I would like someone to check the logic of this solution. First of all, I am not an electrical engineer or auto mechanic but I do have a good understanding of electronics.

According to the service manual, fog light operation is controlled by the Intelligent Power Distribution Module (IPDM) which is located in the engine compartment. Again according to then manual, the way the IPDM controls the fog lamps is by applying and removing a path to ground (depending on the position of the headlight switch and fog lamp switch) which then allows power to flow through the fog lamp relay lighting the fog lamps. The same mode of operation is used to light the tail, parking and marker lights.

I propose that a jumper be used from the ground side of the coil of the tail/parking relay to the ground side of the coil in the fog light relay. Therefore, when the IPDM provides the ground for the tail/parking relay it will also provide a ground to the fog light relay turning on the fog lights with the parking lights.

My only concern is that the fog lights may be illuminated at all times with the parking lights. This solution may not allow parking lights only.

Let me know what you think. I want ALL comments. If this is completely flawed, SHOOT IT DOWN.

Thanks
Bryan

killerslp · 11-19-2004, 11:37 AM

sounds like it will work fine but since the unit control the light by the ground and thats what your going to share with the parking lights the fogs will be on anytime you have the parking lights on. I suggest sharing the ground for the headlights and wire them up like that. the fog light switch won't work but anytime your headlights are on the fogs will be too.

scsTiTan · 11-19-2004, 04:16 PM

It sounds like it should work exactly as you say, however I am not an EE guy so...I would like to hear the results of this if you do try it. I would like my fogs on with the parking lights, but being able to turn them off independently would be a nice feature to have. Here in OK it is illegal to have both headlights and fog lights on at the same time - stupid law - I have been stopped a few times in the wifes Santa fe, but only given warnings so far. Keep us updated on what you do and how it turns out.

Thanks,

jasonwabc · 11-19-2004, 04:23 PM

I was a unhappy when I just installed my new turn signal switch and fog lights to find that they only work with the headlights....I like the way dodge trucks let you run them with the parking lights.....we need a mod!

killerslp · 11-23-2004, 02:59 PM

splice into the parking light power wire and run it to a switch in the cab, run the other wire from the switch to the lights. Then hook the ground from the parking lights directly to the fog lights. with that setup the only time the fog lights will be able to turn on is when the parking lights are, but you will still have a switch to shut them off seperately. If you are using high power fog lights you will want to add a relay right after the switch for the fog lights, the relay will have 1 wire from the switch, 1 ground, 1 running to the foglight + side and finally a fused power wire from the battery.

*OnebadSE* · 11-23-2004, 06:12 PM

Makes no sense to have the fogs on unless the headlights are on. What's the point? They're useless otherwise. They don't put out enough light to be of any real use on their own.

Titan Ken · 11-23-2004, 08:37 PM

With my Tundra it was an easy to re-route the "trigger" voltage for the fogs from the headlight circuit to the parking light circuit. This way you could have the fogs on when the park lights were on (and the headlights, plus high beams) but still maintain independent control of the fogs.

I like to use the fogs with the parking lights during the day time, like day time running lights.
Agreed, they do not put out enough light to use alone at night.

With the ultra-high tech wiring of the Titan with computer controlled wiring circuits, a fog light mod like I did in the Tundra is much more difficult.

BigRedTitan · 11-23-2004, 08:43 PM

bg478, your idea sounds like it would work. If you want to be able to turn off the fogs when the parking lights are on, just run the "jumper" into the cab to a switch and back to the relay. I ran a separate circuit for my fogs and kept the original turn signal stalk. I did a "how to". Here is the link to it... Parking Lights WITH FOG LAMPS!!

pciley · 11-23-2004, 10:28 PM

I just put them on a seperate circuit, kind of stand-alone like. They are powered by a fused 12V lead from the battery and the ground is broken in the cab by a switch that was used in a prior-year's Pathfinder that fit PERFECTLY in the empty knock-out plastic cover on the driver's side kick panel to the left of the steering wheel.

You can turn on the fog lights whenever you want, to flash another driver, to set up camp at night, countless other times you might want to do so.

The switch also lights up to let you know when the fog lights are on, in case you forget when you get out of the vehicle.

terryu1 · 11-24-2004, 05:29 AM

With mountain fog here, using just fogs was always something I did and I think is and option that should be available. In dense fog, distance is not a priority. With fogs and parking lights only you still have tailights but the fogs so close to the ground sometimes make it easier to see the road and the lines. On many occasions the reflection of the headlights in the fog actually make visibility worse. In this dense of fog top speed is usually 20-35 mph (for sane drivers) and once again forward illumination distance is not as important as just being able to see the lines to stay on the road. My two pennies.

killerslp · 11-24-2004, 08:05 AM

Quote:

Originally Posted by pciley

I just put them on a seperate circuit, kind of stand-alone like. They are powered by a fused 12V lead from the battery and the ground is broken in the cab by a switch that was used in a prior-year's Pathfinder that fit PERFECTLY in the empty knock-out plastic cover on the driver's side kick panel to the left of the steering wheel.

You can turn on the fog lights whenever you want, to flash another driver, to set up camp at night, countless other times you might want to do so.

The switch also lights up to let you know when the fog lights are on, in case you forget when you get out of the vehicle.

the only problem with this method is that it's very easy to leave them on. hell people manage to leave their headlights on at night all the time, even with a beeping or dinging noise coming from the dash warning them. Also why would you want to use your fog lights to flash another driver when you can use the headlights just as easy.

Davink · 11-24-2004, 08:43 AM

Quote:

Originally Posted by killerslp

the only problem with this method is that it's very easy to leave them on. hell people manage to leave their headlights on at night all the time, even with a beeping or dinging noise coming from the dash warning them. Also why would you want to use your fog lights to flash another driver when you can use the headlights just as easy.

So rather than running a seperate battery lead, first see if there is an unused circit in the fusebax (there may be depending on the model you have) see if any of them are switched, If not simply tape the power off a switched ignition lead, That way the lights can only be on when the car is on. Ofcourse that looses the ability to shut of the truck while using them for things like setting up camp, etc.

Just my two cents.