low beam + driving / fog light wiring (revisited)

[aearch]

so i want the fog lts as per per code i have it wired as per the oem diagram
yet would it be better to add a high beam relay in the circuit
they came stock under the bumper
the hellas

 

[Stevehose]

I have 6 of uncalculated high wattage and a couple shades of yellow, is that too many?

I do have a driving light cutout switch if I don't want them on with the high beams.

Also, the reason fog lights are wired in US cars to switch off when the high beams are illuminated is to comply with a federal regulation limiting the number of forward facing lights than can be used at any one time.

 

[Markos]

I do have a driving light cutout switch if I don't want them on with the high beams.

That is what I have done in the past. The switch power came directly from the high beam wire in the dash, and the switch simply triggers the driving light relay,

 

[sfdon]

I do like the setup where the ground wire of the foglight relay is connected directly to the highbeam filament.
With highbeam off the filament is a ground.

 

[sfdon]

Relay one (high)
pin 30 battery+
pin 85 ground
pin 86 to switch (high)
pin 87 to pin 85 of fog relay

Relay two (fog)
pin 30 battery+
pin 85 3 wires total, 1 wire to pin 87 of high beam relay, one wire to each high beam bulb
pin 86 to fog light switch
pin 87 two wires, one to each fog light

 

[DWMBMW]

Mine is a euro and came with the fog light green button. With the button depressed they come on with the low beams but turn off once the high beams are selected (the green button still stays on and illuminated). Although my front turn indicators only come on with the the blinkers.

 

[aearch]

cant i leave the oem and just add a relay to run the high beams
wire to high switch to 85 and 87 to lights
just interupt the hot wire to the lights w
a relay

 

[Gary Knox]

Scott,

I have a set of e28 fog lights mounted below the front bumper for DRL's. I installed lower wattage bulbs in them (I'[l NEVER drive the car in the fog!). They are wired to turn on whenever the ignition is 'on'. I have a small round rocker switch about 8" below the hazard switch that can turn them off if I want. That rocker switch has a very small green light in it that glows when they are on and is dark when they are off. The switch is easily reached when driving. Switch picture is attached.


Gary

 

[Markos]

I have a set of e28 fog lights mounted below the front bumper for DRL's. I installed lower wattage bulbs in them (I NEVER drive the car in the fog)

Gary

That seems like a good use case that I overlooked in my rant above. When my daily had H4’s, I always drove with my city lights on. I’m sure someone in europe would smack me upside the head for doing that.

 

[rsporsche]

@restart doesn't have a question or a solution above. @rsporsche didn't really have a question (or solution) either, just a set of ideas. What is your lighting goal? I noticed in another thread that you want your fogs to run independently of your low beams. I have to ask why?

Here are my general opinion on how lights should function, with the intention of lighting the road, not looking cool:

1. Headlight switch in parking light mode engages parking lights and/or city lights
2. Headlight switch fully engaged turns on low beams
3. High beam switch engages high beams, low beams (and fogs) turn off
3a. Optionally, low beams stay on
5. Driving lights come on with high beams
6. Fog lights come on with low beams

Regarding #5. If your driving lights are independent of your high beams, that means that you are going around a bend and have to reach for a switch on/under your dash to disable lights that are more blinding than a high beam. You want to be able to quickly disable your driving lights with your high beam switch. Also, driving lights are for distance. If your interest is lighting, there is no real reason why you wouldn't want them on in conjunction. Driving lights should be mounted above the bumper.

Regarding #6. Unless you are driving through pea soup, there is no reason to have your fogs run independently from your low beams. There are instances where it is so foggy that your low beams are bouncing off the fog, and the independently lit fog lights are cutting through the fog near ground-level. For that reason, fogs should always be mounted under the bumper. Unlike driving lights, if you do mount them independent of the low beam switch, there are no implications related to oncoming traffic. Fogs should use a low wattage bulb. Their value is a wide low pattern, not brightness.

#6 - fogs can be mounted higher if their intention is to provide cornering lights. in ATL we don't have a lot of fog, but a lot of hills / curves.

 

[Markos]

#6 - fogs can be mounted higher if their intention is to provide cornering lights. in ATL we don't have a lot of fog, but a lot of hills / curves.

Agreed. I will update my rant. If you mount your dogs above the bumper, be sure to rotate the lenses accordingly.

 

[Markos]

cant i leave the oem and just add a relay to run the high beams
wire to high switch to 85 and 87 to lights
just interupt the hot wire to the lights w
a relay

@aearch,

That is exactly how one would normally add a lighting relay to a headlight circuit. On the coupe, I would get a solid understanding of what the existing high beam can relay does. I have done zero research on coupe wiring and I personally don’t understand the function of the relay.

 

[Ohmess]

@aearch,

That is exactly how one would normally add a lighting relay to a headlight circuit. On the coupe, I would get a solid understanding of what the existing high beam can relay does. I have done zero research on coupe wiring and I personally don’t understand the function of the relay.

Yeah, I thought all our cars had high beam relays. I know my 72 does. The original question appears to relate to the addition of a low beam relay to the circuit. If so, interrupting the hot wire to the lights and using it to initiate the relay is the correct process.

 

[aearch]

THE 74 ONLY HAS A LOW BEAM RELAY
and the high beams run from the fog light switch which is hard to make work as im trying now