Combining high and low beams

**LRT** · 18th June 2011, 08:48 PM

Fantastic Paul. Thanks for your detailed information. Although we could fit fog lights and extra driving lights as other forum contributors have well suggested, they may not solve the problem of the dark central patch of the DII low beam when high beam is dipped, which we also experience, especially in off highway night driving in foggy conditions. On bitumen highways and roads this black spot is not a problem when dipping high beam to low beam, even at 110 kms per hour. But on gravel roads with grassy edges, this black spot is serious, even at much lower speeds.

We regularly travel on gravel roads and meet with patches of heavy fog. If the high beam is left on, it just shines up into the fog with blinding shafts of light. If the high beam is dipped, it is momentarily hard to see the road in front on low beams due to the black spot. But if the high beam is manually held on in flash mode with the low beams still on, visibility is excellent. Indeed, the DII’s combined lights are far superior than the separate fog and driving lights we have had on other vehicles.

It is a relief to know that we will be able to use the DII’s standard lights, as we certainly don’t want to damage them, which would be expensive to replace or upgrade. Your proposed modification to suit the standard globes seems excellent.

LRT

**PaulMc0308** · 18th June 2011, 09:59 PM

The factory fitted fog lamps fill-in the dark area perfectly and, as a bonus, light-up the roadside verges and ditches immediately to the front and to the sides of the car.

Where I live is mostly rural lanes, so in the dark, you usually get plenty of advance warning of vehicles coming the other way and have time to switch the fog lamps off and dip your main beams, but it's a PITA to have to do it manually each time.

Unfortunately, it's not legal here to use front fog lamps in anything other than conditions of reduced visiblity, i.e. - mist, fog, heavy rain (darkness doesn't qualify

)

BUT, if you use them with main beams, they are legal if they extinguish when you dip your lights as, in the eyes of the law, they become 'Auxiliary Lamps' - regardless of beam pattern and mounting position.

I'm currently thinking of either putting some extra fog lights in the below-bumper grille, that only come on with main beam, something like this -

(that's not my DII - the pic. is from here -Land Rover Owner • View topic - new spots )

but using a pair of rectangular(ish) Hella FF75 Fog Lamps (which I already have) -

Or modfying the factory fog lights circuit so that I have the option for them to switch on when main beam is selected.

Off the top of my head, this would involve a latching switch and a changeover relay, but this might be complicated by virtue of the fact that the front fog lamps are controlled by the BCU.

As an aside, if your front fog lights won't stay illuminated with main beam (some markets don't allow this combination), the setting in the BCU can be changed -

You'll need to use a suitable plug-in diagnostics tool to change this setting, there are three options for front fog lights -

None - The vehicle is not fitted with front fog lamps

No Main - The front fog lamps will operate if the headlamps are on main beam

Main - The front fog lamps will not operate if the headlamps are on main beam

The above 'Non-CLASS' settings descriptions are from the Technical manual in RAVE, but 'Main' and 'No Main' seem to be the wrong way round to me

Paul.

1989 Arles Blue 2.5TD 110 Hardtop
1999 Epsom Green Discovery II 4.0 V8i XS

.

**BigJon** · 19th June 2011, 09:53 AM

Originally Posted by PaulMc0308

Unfortunately, it's not legal here to use front fog lamps in anything other than conditions of reduced visiblity, i.e. - mist, fog, heavy rain (darkness doesn't qualify

)

.

It isn't legal in Australia either, but that doesn't stop lots of ignorant and/or selfish people from driving around with them turned on all the time.

**LRT** · 20th June 2011, 10:09 AM

Many thanks PaulMc0308 for your helpful comments on the DII fog lamps. It is a relief to know that they will fill in the low beam blackspot as they are quite expensive to purchase. It was good to see pictures of your proposed central lights below the number plate, which may well be better suited for the country road driving that we both experience, rather than DII factory fog lamps.

Would the DII standard alternator need to be upgraded in order to run both the factory fog lamps and your proposed centre lamps with the high beams on?

LRT

**PaulMc0308** · 20th June 2011, 07:35 PM

Originally Posted by LRT

Many thanks PaulMc0308 for your helpful comments on the DII fog lamps. It is a relief to know that they will fill in the low beam blackspot as they are quite expensive to purchase. It was good to see pictures of your proposed central lights below the number plate, which may well be better suited for the country road driving that we both experience, rather than DII factory fog lamps.

Would the DII standard alternator need to be upgraded in order to run both the factory fog lamps and your proposed centre lamps with the high beams on?

LRT

I think that the standard Alternator is more than man-enough for the job -

The TD5 Alternator has a 120Amp output

The V8 Alternator has a 130Amp output

Paul.

1989 Arles Blue 2.5TD 110 Hardtop
1999 Epsom Green Discovery II 4.0 V8i XS

.

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