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Defender sidelights within headlamp unit


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Hi

I have a 1996 Defender 90 CSW.  It has 4 sidelights at the front, 2 conventional and the other 2 are inside the headlamp unit that are ignition controlled but also only illuminate when the vehicle sidelight switch is operated.  The 2 in the headlamp unit are not separate bulbs but utilise the main dipped/main beam bulb but at low power.   Does that make sense?

The 2 inside the headlamp unit have stopped working (both at the same time).    I need to trace the fault so need to know how these are wired in please.  Is there a relay somewhere that may have failed . . . ?

 

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Yes that makes perfect sense, it's known as "Dim/Dip" and it's where the headlight dipped beam filaments are illuminated at low power, (through a resistor,) when sidelights and ignition are on.

As far as I know it was introduced due to upcoming regulations some years ago which I believe were never implemented and are not a legal requirement, although the function continued well into the Td5 generations, (my 2004 90 had them.)

There is a relay which controls this function, on a Td5 it's behind the dash binnacle, it's possible either the relay itself has failed or maybe the resistor has given up. To be honest though, a lot of defender owners have disabled the function either by removing the relay and by-passing it or simply disconnecting the resistor. It looks like yours has pre-empted this and taken it upon itself to self-disable.

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Not sidelights but the dim dip system, only works when engine is running as the signal comes via the switching relay from the oil pressure switch. this dim dip unit & its associated resistor put the dip beam on at about 10% brightness, to disbale it there are 2 ways, remove the pink cased relay & fit a jumper wire between the 2 blue with red trace wires in the relay socket, or in right rear corner of engine bay at the wing top rear edge unplug the resistor.

that will give you these front light

ign off or on & main light switch to 1st position - normal side & tail lights 

engine running same as above BUT no dim dip in headlight units,  The dim dip law & requirement was ditched in 2006 I believe, since been superseded by the daytime running lights. Dim Dip is not a legal requiremet & NOT a MOT test item.

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The resistor is fixed to the offside inner wing and the relay is behind the dash binnacle.

I, like most others, got rid of the dim-dip years ago. I don’t think I can remember a single time where I’ve only had my sidelights on and not the headlamps as well, so couldn’t see a point to it. 

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Dim dip is a unreliable system, I removed mine & replaced headlights with the Wipac crystal lense version with seperate sidelights in the headlight unit, these are 5watt bulbs that fit in a seperate push in rubber holder & wired them to the existing wing mounted sidelights. also change the dip/main bulbs to Osram nightbreakers 150% brighter wired via 2 relays & thicker wiring powered direct from alternator output , one for dip beam & 1 for main beam, the light output is far better.

 

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Not meaning to hiJack this post, but I have read (on here I think) that reducing the voltage on a halogen bulb causes them to deteriorate  faster? does anyone have any facts / experience of Dim Dip to back this up?  Conventionally with incandesnt for every 5% you reduce the voltage across and incadescent you double the bulb life.  Until I heard of Halogen 'depletion' I was planning on wiring my spots etc so that when 'off' they would recieve enough volts (via a resistor) to keep them glowing stopping, (or so I thought) the shock of the bulbs going from cold to flat-out, and back again.

Beware topic diversion:

- having a Christmas light 'fetish' (my Wifes description, - I do put 20 sets on our tree every year) I have systematically taken sets and added 10% extra bulbs (from identical sets - I learned this the hard way!)  It definitely works in terms of increasing the bulb life, and I spend substantially less time tracing and swaping dead bulbs.

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I don't know about the bulbs having a longer life, but the dim dip system is unreliable, the early system that uses the black box just burns out one or more components inside, my 110 went through about 6 units before I decided to ditch it. 

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Does anyone know what the value (in Ohms) that resistor is?  and what the rated wattage is?

If you wanted a dim dip you could buy a resistor with a higher rated wattage (and perhaps mount it on somthing that would help it disipate the heat better - this could be anything from a small heat sink to a off-cut of copper or brass sheet, or steel)

These people can supply these resistors (and a huge range of other stuff) 

https://cpc.farnell.com/w/c/electronic-electrical-components/resistors/prl/results?st=Resistor&power-rating=200w

and this is an example of a heat sink:  (with absolutly no guarantee that this will fit your restistor - you will have check the internal dims carefully to match them)

https://cpc.farnell.com/h-s-marston/07wn-01000-a-200/heat-sink-undrilled-1-8c-w/dp/SC00636

If you uprate your resistor enough - you wont really need the heat sink 

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some info on resistor ohms here ---- The UK was the only country to introduce a dim-dip system. The simplest such system merely consists of a relay and a 0.5 to 1 ohm resistor. This causes the dipped headlamps to light up automatically at reduced intensity whenever the engine and the side lights are switched on. Side lights can still be used on their own when parking, and dipped headlamps for any roads at night when they are necessary to illuminate the road.

found the above here http://dastern.torque.net/techdocs/dimdip.html

this from Wikipedia

Dim-dip lamps

UK regulations briefly required vehicles first used on or after 1 April 1987 to be equipped with a dim-dip device[41] or special running lamps, except such vehicles as comply fully with UN Regulation 48 regarding installation of lighting equipment. A dim-dip device operates the low beam headlamps (called "dipped beam" in the UK) at between 10% and 20% of normal low-beam intensity. The running lamps permitted as an alternative to dim-dip were required to emit at least 200 candela straight ahead, and no more than 800 candela in any direction. In practice, most vehicles were equipped with the dim-dip option rather than the running lamps.[41]

The dim-dip systems were not intended for daytime use as DRLs. Rather, they operated if the engine was running and the driver switched on the parking lamps (called "sidelights" in the UK). Dim-dip was intended to provide a nighttime "town beam" with intensity between that of the parking lamps commonly used at the time by British drivers in city traffic after dark, and dipped (low) beams; the former were considered insufficiently intense to provide improved conspicuity in conditions requiring it, while the latter were considered too glaring for safe use in built-up areas. The UK was the only country to require such dim-dip systems, though vehicles so equipped were sold in other Commonwealth countries with left-hand traffic.[42]

In 1988, the European Commission successfully prosecuted the UK government in the European Court of Justice, arguing that the UK requirement for dim-dip was illegal under EC directives prohibiting member states from enacting vehicle lighting requirements not contained in pan-European EC directives. As a result, the UK requirement for dim-dip was quashed.[41] Nevertheless, dim-dip systems remain permitted, and while such systems are not presently as common as they once were, dim-dip functionality was fitted on many new cars well into the 1990s.

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On 3/2/2020 at 7:19 PM, Oakmaster said:

Not meaning to hiJack this post, but I have read (on here I think) that reducing the voltage on a halogen bulb causes them to deteriorate  faster? does anyone have any facts / experience of Dim Dip to back this up?  Conventionally with incandesnt for every 5% you reduce the voltage across and incadescent you double the bulb life.  Until I heard of Halogen 'depletion' I was planning on wiring my spots etc so that when 'off' they would recieve enough volts (via a resistor) to keep them glowing stopping, (or so I thought) the shock of the bulbs going from cold to flat-out, and back again.

 

Quartz Iodine lamps now called halogen are supposed to run at 13 volts otherwise lamp deteraion will take place. That is from the originol QI information supplied by Phillips when QI first came out. 

Halogen lamps do not have a bulb but a quartz envelope

Another bit of usless information The QI lamp filament runs a 3,100 Deg C

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  • 2 weeks later...

Can we ask what you did in the end?

and because Id quite like to build a 'dim dip' (putting me in a minority of one I'd guess) Where there 2 resitors (one per headlamp) or two.

If I do this I'd include them within a  alternator-fed system, using 6 relays 2 each side dipped and main separately, plus dim dip, fed with heavier wire - its a lot of relays and wire, but it would / should be 4 times as reliable.

luckilly I never had to delve into the dreaded black box, can anyone tell me if it was 1 or 2 resistors, and the resitance in Ohms (Western has said between 1 and 0.5 Ohms - did this change?)  and their rating in Watts.

No big deal if nobody knows! I'll have to experiment.

Thanks

 

B

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3 hours ago, Oakmaster said:

Can we ask what you did in the end?

and because Id quite like to build a 'dim dip' (putting me in a minority of one I'd guess) Where there 2 resitors (one per headlamp) or two.

If I do this I'd include them within a  alternator-fed system, using 6 relays 2 each side dipped and main separately, plus dim dip, fed with heavier wire - its a lot of relays and wire, but it would / should be 4 times as reliable.

luckilly I never had to delve into the dreaded black box, can anyone tell me if it was 1 or 2 resistors, and the resitance in Ohms (Western has said between 1 and 0.5 Ohms - did this change?)  and their rating in Watts.

No big deal if nobody knows! I'll have to experiment.

Thanks

 

B

I actually like the look of the dim dip lights, I just wanted to improve the main beam. I hadn't considered re-instating it but sounds an interesting idea.

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13 hours ago, Oakmaster said:

Can we ask what you did in the end?

and because Id quite like to build a 'dim dip' (putting me in a minority of one I'd guess) Where there 2 resitors (one per headlamp) or two.

If I do this I'd include them within a  alternator-fed system, using 6 relays 2 each side dipped and main separately, plus dim dip, fed with heavier wire - its a lot of relays and wire, but it would / should be 4 times as reliable.

luckilly I never had to delve into the dreaded black box, can anyone tell me if it was 1 or 2 resistors, and the resitance in Ohms (Western has said between 1 and 0.5 Ohms - did this change?)  and their rating in Watts.

No big deal if nobody knows! I'll have to experiment.

Thanks

 

B

One 300tdi vehicles there was only 1 resistor in the right rear corner of engine bay, 

On earlier vehicles the black box did the job of control & housing the resistors, I've had 7 units fail in the last 20 years, got fed up of changing them, so just unplugged it & ran without dim dip, later I fitted so crystal lense headlights that have the sidelight in, this is just as good as dim dip, gives the look but no unreliable items to burn out. 

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