One for Jeremy

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Oscar
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One for Jeremy

Post by Oscar » Thu May 11, 2006 5:50 pm

Hi jeremy

You've mentioned replacing wiring and earths a couple of times to improve headlights' performance. Any chance you could write it up for electrical dummies like me? Or give me a few pointers, and I will write it up.

Especially interested in tools and materials needed, so that I don't get halfway and discover I need some obscure part. And potential pitfalls.

Oscar
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Post by ed4ferrets » Thu May 11, 2006 6:46 pm

I second the request for bright :idea: :idea: :idea: :idea:
Marty said: "Take some small comfort from the fact that the driver of the other car, having failed the breath test will even now be in a little cell, with luck they will double him up with some mean bastard who will be tattooing a fandango on his arse"

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Post by Vanny » Thu May 11, 2006 11:03 pm

Big wire, round crip connector, blade crimp connector, self drilling or self tapping screw!

The earth does make a very noticable difference but changing the earth and putting a relay in makes the biggest difference, a sat and did this on the old 19rd and compared the results against standard with new bulbs and WOW what a change it makes!

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Post by ed4ferrets » Thu May 11, 2006 11:08 pm

Earthing I understand, installing relays is a mystery to me :?
Marty said: "Take some small comfort from the fact that the driver of the other car, having failed the breath test will even now be in a little cell, with luck they will double him up with some mean bastard who will be tattooing a fandango on his arse"

'94 XM 2.1TD Break
'99 Xantia 1.9TD Break (almost there)
'63 Renault Caravelle

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Post by jeremy » Fri May 12, 2006 9:00 am

A relay is simply an electrically operated switch. The ones you require for the headlights have 4 terminals, 2 operate it and 2 are the switched terminals. Most relays have their circuit printed on them and the operating part is shown as 2 terminals with a coil between them, and the switched terminals are shown as a switch.

What you are aiming to do is to feed the headights straight from the battery via a thick cable. You need the relay to switch this cable in a position that enables you to keep the feed to the headlights as short as possible so as to reduce voltage drop in the cable. (all cables produce a voltage drop - it gets worse with long runs of thin cable as in the original car wiring.)

So you wire the operating (coil) circuit using the existing main beam wiring to operate it and connect the other side of the operating coil terminal to earth - one switch which clicks nicely when the headlights are on main beam.

the power circuit is taken from the battery positive terminal. probably the easiest and best method is to get a large ring terminal and put it under the battert terminal clamp nut. Run a thickish wire from there to the relay switched terminal, and another from the other switched terminal to the headlight main beam - and hey presto you have a one bright eyed monster!

What you do with the other headlight is a matter of choice. You can either double up on the switched output from the relay or repeat the process using another relay and use one for each side.

It is important that some form of protection is used - ie a fuse. My own preference is to fuse it as close to the battery as possible and reduce the amount of unprotected wiring and system by as much as possible. the other thing to be considered is safety - and you will find that BX headlights are NOT fused but the sidelights are. Obviously the risk of a fuse blowing is that you will be plunged into total darkness - so if you do each headlight separately using a relay for each the risk of both failing together is reduced to virtually nil.

I have not dealt with the dip beam. Primarily this can be treated in the same way BUT your car probably has dim-dip and I'm not quite sure how to eliminate that - or for that matter what the legal requirements are. I know that dim dip has now been dropped in the interests of avoiding European civil war (sorry - harmonization - and providing work for the overpaid) but what the position is if you remove it from a car fitted with is is I don't know.

The earth is also vitally important and must be good. better earthing arrangements will probably improve things on their own.

The wiring diagram can be found here.

http://www.rwbsmith.plus.com/citroen2/Electrical/

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Post by RichardW » Fri May 12, 2006 9:53 am

He he he.... if you've got a car with dim-dip and you stick relays in the head lights, all sorts of weird things will start happening 8) (well, it is a Citroen after all!). What happens is that the dim dip relay actually earths through the main beam filament. Stick some relays in, and the dim dip loses the plot :lol: There is no requirement for dim dip, so the solution is just to pull the dim dip relay out, and all will be OK.

All you have to do is find the relay :twisted: I can't remember exactly where it is, but on the back of the bulkhead in the scuttle area rings a bell.
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Post by Oscar » Fri May 12, 2006 10:31 am

Oh Christ. What's a dim dip? (and why do I feel like one?)

When I switch the lights on, one twist of the stalk turns on the sides, another twist the dipped main beams, and to turn on full main beams, I pull the stalk towards me once, same to revert to dipped mains.

Is that a dim dip?
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Post by DavidRutherford » Fri May 12, 2006 10:37 am

Dim dip was a system introduced in the UK in about 1987ish that prevented a car being driven on sidelamps alone.

So, when the sidelamps are on, and the engine running, the dipped beam headlamps are switched on as well, but at a lower voltage (usually through a dropping resistor) This doesn't affect the normal dipped or main beam.

You can tell if you have this system. Park facing a wall with the engine running, and the headlamps on dipped beam. Now turn the stalk to sidelamps. Is the dipped beam pattern still there, but dimmer now? Now turn off the engine. The dim dip pattern should dissapear, and you'll be left with just the sidelamps.

DIm dip isn't tested for at MOT, and as far as I know has been pretty much forgotten. I've had a couple of older Cavaliers in which the dim dip resistor burned out, and left the car "standard" (No dim dip) Was like that for years, and many MOT's.

The system was phased out in about 1997 I think.
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Post by Vanny » Fri May 12, 2006 11:25 pm

Is it phased out? Most newer cars (certianly on VAG's and BMW's that ive noticed) still have side lights and dipped beam, though the new style mini's dont (they just have the Landy stlye side lights and nothing more), i wonder if this is just a particular model quirk?



As for the wiring, consider you wiring as a plumbing system. You have a header tank (the battery positive terminal) and a waste pipe or drain ( the battery negative terminal). So you have a load of pipes (the wires) around which water flows (or in the case of wires, electricity flows), and your water will ALWAYS flow from the highest point to the lowest point, from water tower to drain. For electricity it will flow from water tower to the drains, but remember the water will always find a way to the drains, even if its through your damp course layer! It the case of electricity it will always from form the battery to the lowest level which should be the battery negative terminal!

As your pipe get old, scale build on the insides and slows the flow of water through them, exactly the same happens with electricity through old wires. As your car gets older the lights get dimmer as less electricity gets to them, so what you need to do is put a new short piece of wire from the highest point of electricity to the lights, ie from the battery to the bulb!

This is where the relay comes in, its a valve, and when electricity runs through this valve, it bridges a gap between the head light and the battery! There pretty easy to understand, but hopefully with the water analogy it might be a little simpler to the elcetricity beginners!



For those of us who are learned, i am well aware that there is no such thing as electricity as a measurable quantity, and thus it does not flow. Current flows, well actually it doesnt, gaps flow and electrons get outta the way and the resultant effect is inverse current flow though some old todger gussed and got it wrong so it's accepted that current flows, and i'm well aware of this as well. However before the many experts go ripping into the amazing water analogy, i will clarify that i am dgree qualified in electronics, and have been taught to teach electronics to A-level standard, and the water analogy is the way to do it! Except when it comes to flip flops and multi stables, there just a pig to make as a water analogy!

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Post by jeremy » Fri May 12, 2006 11:44 pm

As David says Dim Dip is a creation of the 80's and in reality is quite a nice device - and I use it often on the BX.

Later cars (as with earlier cars) have separate side lamps and dip beams - or may have them combined. What the dim dip does is prevent you driving around on side lamps alone by lighting the dip beam partially if you try do do so. As he says - engine off - sidelights switched on - side lights will light, start engine and don't touch light switch and dip lights will come on on dim dip.

Consigned to the dustbin of history now - along with - dimming brake lights - anyone remember them? We just got them fitted to late 60's and early 70's cars when someone invented the rear fog light and they were forgotten. Purpose was to stop Barbara Castle (who as Minister of Transport didn't drive and invented the 70MPH speed limit) and being dazzled by brake lights when sitting in her government car.

I had dimming brake lights on my Triumph Stag - a hugely complicated relay with external resistors on printed circuit boards stuffed in the back wing - the idea was that with the sidelights on the brake lights dimmed - handy in fog! I recall immobilising the thing by pulling off the earth wire!