Driving/fog lights

[Nine40]

Are the fog/driving lights built into headlights? If i switch lights on then the dash switch on the headlights light up pointing to pavement another press and rear fog come on..nithing in handbook that i can see.

[Forrest]

Yes. The inner part (nearest the grill) of the headlamps contains two separate h3 lamps. The lower ones are fog lamps and the upper ones are driving lamps which come on with main beam.

[Ian21401]

As Forrest states. The headllamp unit is three lights in one. Ahead of it’s time when originally fitted to the 900 series but now quite common place with the exception of the “fog lamp” section in the inner lower corner. My understanding of the lighting regs. is that as that as the centre of the illuminated area of that part of the light unit is more then 24 inches above the road level, strictly speaking it is not a “fog lamp” and hence may be used on occasions when a traditional “fog lamp” ,the centre of which is less than 24 inches above the road level may not be used. If mounted at less than 24 inches “fog lamps” may only be used in fog or falling snow.
The “fog lamp” switch, which as you know is separate from the main lighting switch, annoys me as there are occasions when I would like to have the rear fog lamps on without the fronts on, eg. heavy spray behind me on a major road.

[jonnyf90]

Originally Posted by Ian21401

As Forrest states. The headllamp unit is three lights in one. Ahead of it’s time when originally fitted to the 900 series but now quite common place with the exception of the “fog lamp” section in the inner lower corner. My understanding of the lighting regs. is that as that as the centre of the illuminated area of that part of the light unit is more then 24 inches above the road level, strictly speaking it is not a “fog lamp” and hence may be used on occasions when a traditional “fog lamp” ,the centre of which is less than 24 inches above the road level may not be used. If mounted at less than 24 inches “fog lamps” may only be used in fog or falling snow.
The “fog lamp” switch, which as you know is separate from the main lighting switch, annoys me as there are occasions when I would like to have the rear fog lamps on without the fronts on, eg. heavy spray behind me on a major road.

If you're pretty savvy with a soldering iron you can retro fit separate switches from a 740, one for rear fogs and one for fronts. You can use the requisite wires for each and use a common ground. Will throw together a sketch if you like?

Cheers

[Ian21401]

Thanks jonny, I’d thought of investigating that possibility some time but never actually done anything about it as there always seems to be something more important to attend to.

[Laird Scooby]

Originally Posted by Ian21401

My understanding of the lighting regs. is that as that as the centre of the illuminated area of that part of the light unit is more then 24 inches above the road level, strictly speaking it is not a “fog lamp” and hence may be used on occasions when a traditional “fog lamp” ,the centre of which is less than 24 inches above the road level may not be used. If mounted at less than 24 inches “fog lamps” may only be used in fog or falling snow.
The “fog lamp” switch, which as you know is separate from the main lighting switch, annoys me as there are occasions when I would like to have the rear fog lamps on without the fronts on, eg. heavy spray behind me on a major road.

Not quite correct, a fog lamp can be mounted anywhere between ground and 1200mm from the road surface. As such, the higher position of the fog lamps on the 7/9xx models with them built into the headlamps is still perfectly legal for all normal uses of front fog lights.

When i passed my test, the three times when front and/or rear fog lamps could be used are :

1 - in fog - no surprise there!
2 - in heavy rain
3 - in falling snow

They seem to have rationalised this now to "When visibility is reduced to 100m or less".

If the visibility is reduced to the point where you want the rear, high intensity fog lamps on so Mr Magoo has less chance of rear-ending you, there's a pretty high chance you need the front fogs on as well.

Also in rural areas where there is little or no edge marking on the roads or what there is is covered in mud, front fogs are benefical as they give a wide, low beam spread. As long as the top of the fog lamp beam remains below the main, horizontal part of the dipped beam light, it's all legal in terms of not dazzling oncoming road users.

However an over-zealous copper may argue this point as technically it might not be raining heavily, snowing or foggy.

Best way then is to show them because dipped beam on (certainly the 760 which shares a similar headlamp to the 9xx) is pretty narrow and doesn't give good illumination of the kerb area.
With all the potholes down rural roads, lack of edge markings, dirty roads etc, a very presentable argument can be made for using front fogs for your own safety down these roads - in fact i have seen police vehicles locally doing exactly that.

Volvo designed the headlamp reflector to include the front fog so this moves with the main reflector. This means as long as your dipped beam is aligned correctly, the front fogs will also be correctly aligned.

On some models, there is a separate adjustment for the inner driving lamps height. This can be checked with a beam setter machine at MoT time if you talk nicely to the tester. Make sure he understands they are long range driving lamps though or you could end up with a main beam that doubles as extra fog lamps!

[jonnyf90]

Originally Posted by Ian21401

Thanks jonny, I’d thought of investigating that possibility some time but never actually done anything about it as there always seems to be something more important to attend to.

Here we go.
Left side shows what you’ll have in your 940, right would be two switches from a 740/760. The wire colours might be different depending on the year but I’ve listed the socket numbers which are marked on the multi connectors 👍

940 switch lighting is done via some rubbish prism thing with one bulb. If you have the dash apart, upgrade to 1 bulb per switch (like in the 740s, blue bulb holders). If you’re getting switches from a scrappy, get the bulbs too. You can piggy back the lighting off the existing wires (white & black or blue).

Cheers!

[wrinkles]

On the later 940 they have a separate switch for rear fog lights.

[jonnyf90]

Originally Posted by wrinkles

On the later 940 they have a separate switch for rear fog lights.

Yes my late 96 960 does even though earlier ones had a combined one like my 96 940 👍
Maybe to use up the unused switch holes in the dash 🤣

Cheers

[360beast]

Originally Posted by wrinkles

On the later 940 they have a separate switch for rear fog lights.

I was going to say I didn't know what was going on when everyone was saying they are on the same switch.