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Discovery II - Improving Headlamp Light Output on Main Beam


PaulMc
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My 1999 Discovery II (with H4 headlamps), like my old Range Rover, switches off the dipped beam when switching to main beam.

You can see the effect of this by 'flashing' - as this flashes the main beam, without extinguishing dipped beam.

But, when you pull the switch all the way back to latch on main beam, the dipped beam extinguishes, throwing most of the light 'down the road' leaving a (relatively) dark area in the foreground.

I had been using my front fog lamps to fill-in this dark area, but this is a pain as they have to be switched on separately and don't extinguish when you dip the main beams.

I've now 'fixed' this annoyance, by releasing the Blue/Red (UR) wire's terminal from cavity 2 on the Lighting Switch Connector (C0041) and moving it to cavity 1 - dipped beam now stays on with main beam (as per some other markets) :D

post-148-126996094653_thumb.jpg

I will be making some other improvements to the headlamp wiring in the near future, by installing relays for the left and right dipped and main beams (4 x relays) and increasing the size of the feed and earth wires at the same time.

.

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Useful info, cheers.

Mine already does that (both on together) "as per other markets" so I wonder if this can also be set using the Nanocom/Test Book?

I had a look through RAVE at the programmable options and that isn't one of them.

Looking at the circuit diagram, it appears to be good-old-fashioned switching, with no involvement of the BCU or IDM (unlike the front fog lights :( )

Is yours a facelift?, if so, they have separate main and dipped beams, which do stay on together.

Mine is a '99 with H4 headlamps.

.

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I had a look through RAVE at the programmable options and that isn't one of them.

Looking at the circuit diagram, it appears to be good-old-fashioned switching, with no involvement of the BCU or IDM (unlike the front fog lights :( )

Is yours a facelift?, if so, they have separate main and dipped beams, which do stay on together.

Mine is a '99 with H4 headlamps.

.

Ah, yes, mine is a facelift. Sorry :rolleyes:

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Does this mean that both filaments are now on inside the H4 bulb? Interesting to know if this shortens the life at all.

Kev

Yes, both on together.

I did wonder about the bulb overheating or having a reduced lifespan.

Trawling around the web, it seems that doing this is a popular modification on motorbikes, with some BMWs already jumpered to enable or disable the feature.

As I said above, I'll be adding relays and heavier gauge wire in to the headlamp circuits, to reduce any volt drop and to reduce the current going through the column switch.

.

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I had been using my front fog lamps to fill-in this dark area, but this is a pain as they have to be switched on separately and don't extinguish when you dip the main beams.

I will be making some other improvements to the headlamp wiring in the near future, by installing relays for the left and right dipped and main beams (4 x relays) and increasing the size of the feed and earth wires at the same time.

Interesting to see if the fog lights can be used as driving lights. As wel LR4x4-ers all know, it's illegal to use fogs when the visibility is better than 100 metres (although you wouldn't believe that - loads of prats drive with them on illegally/unnecassarily).

If they could be changed to driving lights (i.e. come on with full beam) you would get much more use out of them...

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Interesting to see if the fog lights can be used as driving lights. As wel LR4x4-ers all know, it's illegal to use fogs when the visibility is better than 100 metres (although you wouldn't believe that - loads of prats drive with them on illegally/unnecassarily).

If they could be changed to driving lights (i.e. come on with full beam) you would get much more use out of them...

If fog lights are used with main beam and extinguish when dipped, they are regarded as driving lights (the beam pattern of the lamp is irrelevant) and are legal.

There's a thread about this here - http://forums.lr4x4.com/index.php?showtopic=54312

.

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Interesting to see if the fog lights can be used as driving lights. As wel LR4x4-ers all know, it's illegal to use fogs when the visibility is better than 100 metres (although you wouldn't believe that - loads of prats drive with them on illegally/unnecassarily).

If they could be changed to driving lights (i.e. come on with full beam) you would get much more use out of them.

just a case of swapping the trigger wire to the fogs from the sidelight circuit to the main beam circuit

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If fog lights are used with main beam and extinguish when dipped, they are regarded as driving lights (the beam pattern of the lamp is irrelevant) and are legal.

There's a thread about this here - http://forums.lr4x4.com/index.php?showtopic=54312

.

The Fog lamps and any Driving lamps have very different light patterns.

Generally Fog lamps sit low on the bumper. Driving lamps sit above the bumper / grille.(or on the roof)

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The Fog lamps and any Driving lamps have very different light patterns.

Generally Fog lamps sit low on the bumper. Driving lamps sit above the bumper / grille.(or on the roof)

I'm fully aware of the difference in beam patterns between fog lamps and driving/spot lamps tiphat.gif

My point was that if fog lamps are used to supplement main beam, as long as they extinguish when main beam is dipped, the law regards them as auxiliary lights (i.e. driving lights) and they are completely legal to use in this manner.

As detailed in the thread I linked to above, this can easily be achieved by using an ON/OFF/ON switch to select whether the fog lamps are - triggered by side lights / always off / triggered by main beam

.

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