Headlight Modification

[David]

Hi again all.

As everyone is so helpful here I wanted to help some members back with something I know.
As this is my first guide there will probably be something missing, but I will try to explain everything.

I read somewhere a while back about modding the headlights & putting relays on them to make them brighter & cut loads of volt consuming wiring out of the circuit. A question that was raised was "Is it possible to retain the dim dip when adding relays?"

I can safely answer YES!

I have attached a wiring diagram, Sorry for the bad drawing but hopefully you will be able to understand it.

I will also explain any additional mods needed to make it work. There may be slightly different ways of doing it, but this one worked for me.

- Firstly, Things you will need:
* Strong wire, I used 2.5mm to ensure the mod worked optimally.
* Push together connectors, Male & Female.
* New plugs to go to the rear of your headlights
* Fuses.
* The ability to solder.
* 2 relays, a standard 4 pin relay & a 5 pin 2 way relay. The latter is a must for it to work!
* 2 relay holders, a 4 pin & a 5 pin (This point is not essential, but helpful)
* 2 fuse holders (again, helpful but not essential).

Picking fuse sizes: it depends on what wattage bulbs you have in your lights, For arguments sake I will go for 55/80W bulbs. So the formula for working it out is: P=V x I. P being watts, V being volts & I being amps. So (55x2)= 110W dipped beam & (80x2)= 160W for high beam. 110W (divided by)12V = 9.16A. So the best fuse for dipped beam is 10A.. 160W (divided by)12V = 13.33A so the best fuse for high beam is 15A.

- Begin modding!
Its easiest to do the high beam mod & this has probably already been covered somewhere but for the sake of completeness I will show it again.

Both Lights:
You need to pick up power from the battery. I used a ring screwed directly on to the positive battery terminal & a wire from that going straight to the fuses. Keep this as short as possible to avoid possible shorts.

High beam:
Then connect the wiring as the diagram shows.
Pick up power to energize the relay from the old headlight plug behind the left headlight Use a multi meter to find out which is the live wire you require, I used the push together connectors for this so it didn't damages the existing wiring & the mod could be undone is desired. Live is picked up from the fuse you have installed. Its then sent to the high beam lights through the relay.
Earth the negatives somewhere on the body. I used connected them all to 1 wire with a ring connector on the end & connected them with the rest under the battery. Hopefully the diagram should explain any uncertainties.

Dipped beam:
Here's where the fun starts.
As the control module for the dim dipped sends the different voltages to the lights, you can't use the existing wire from the plug as a control wire.
So, you need to disconnect the wire that goes from the headlight switch to the dipped beam in the fuse box. Mark where it goes so you can undo the mod later if you desire.
This wire then needs extending & sending in to the engine bay to go to the control circuit of the dipped beam relay.
The wire from the new relay to the dipped beam lights needs to come from the contact that gets switched between the other 2 contacts (see diagram for reference).
The open without power contact needs connecting to the 12V live you have supplied from the battery & the 5th contact (closed without power) needs to go from the relay to the old dipped beam wire on the headlight plug.

Observations after mod: The dipped beam warning light doesn't work on the dashboard WHEN THE IGNITION IS OFF. Otherwise everything it now works as it used to, only using relays & brighter lights. When the ignition is on the warning light works as it used to. The other headlight warning lights are unaffected. Also note - If you leave the original wire in the fuse box for the dipped beam, when the side lights are on it makes the full dipped beam come on as well.

Everything in the diagram is drawn as if the circuit is switched off.

Feel free to leave any feedback or thoughts.

[Tinkley]

Hope you have checked the extra heat from an 80w filament does not melt the headlamp!..

[Defender110]

, Sorry for the bad drawing but hopefully you will be able to understand it.

Where's the bad drawing? I can only see a very good easily understood drawing!

Nice write up thank you.

[Tim Leech]

Mk1 BX's especially need this mod as the switchgear gets so hot it can melt!

[David]

Hope you have checked the extra heat from an 80w filament does not melt the headlamp!..

Hi, Unless you drive around with high beam on all the time , It will only use the normal 55W filament.
Correct me if I'm wrong, but the standard bulbs are 55W/80W bulbs aren't they? Hence why I used that for the example.

, Sorry for the bad drawing but hopefully you will be able to understand it.

Where's the bad drawing? I can only see a very good easily understood drawing!

Nice write up thank you.

Thanks for the complement.

[mat_fenwick]

I use 55/100 watt bulbs, and have done for the last 5 years or so. I drive mainly on main beam as there's very little winter traffic around here, and if there has been any deterioration it's not yet noticeable.

I've also done a relay mod which retains dim-dip; but to make life interesting/difficult I figured it would be more efficient to do away with the resistor and run the dipped filament in a series/parallel arrangement. It does use six(!) relays though, and a couple of diodes. But the warning lights work correctly

[David]

Hi again, I devised a way to make the warning lights work correctly, but I haven't tested it yet. By using a extra length of wire & 2 semi-conductor diodes...

I thought there might be another way of doing the mod which is why I put 'There may be slightly different ways of doing it, but this one worked for me.' & the proof is such as you have described.
I wonder if someone else has got yet another way of doing it?

It would be interesting to see an actual diagram of how you have done yours.

This forum is a full hive of knowledge, How I've gone on all this time not knowing about it & done lots of points in the mods list I don't know! (Good minds must think alike).

[mat_fenwick]

Many ways to skin the same cat! Here is what I did, but can't claim the credit for the working circuit.

[David]

Thanks for posting that link. That diagram was... interesting. It would have made it slightly easier to read if he put boxes around the relays as I have (just something I'm used to). So my understanding of that, The indicators were tapped into for...? & what does 'main' refer to at the bottom? Otherwise most of it looks straight forward.

At least I know I'm not the only one that's mad with wires; It seems like a common occurrence on here.

[Tinkley]

Std headlight bulbs for BX are 55/60 watt halogen. Alternator power is not a problem or battery so the only potential danger from uprating slightly is the plastic headlight surround getting soft.

I upped my old Morini to a 40/45w headlight - from 30/35w on a 100mph + m/cycle you still didn't see a lot!. The alternator was 100w so a 55/60 conversion used to drain the battery quite a bit.

Fortunately the later bikes had 55/60w so pretty good at night. I am not sure about now but the 80/100w bulbs used to be illegal on bikes......

[electrokid]

Sorry about not having boxes around the relays - I'm used to just showing the contacts as being adjacent to the coil so that's the way it happens in my drawings - unless the contacts are placed far away are are just labelled with relay numbers - now that even confuses me

Everywhere you see the word "main" is a connection to the original feed to the main-beam filaments - so 2 connections at the top plus the one that you asked about at the bottom.

If you are concerned at all about melting things while using high power bulbs then you can get ceramic bulb connectors...

http://www.ebay.co.uk/itm/H4-HEADLIGHT- ... _393wt_725

Interesting mod of yours I wondered about using the original resistors to impliment the dim-dip function and measured the voltage across the bulbs to be (IIRC) around 3.5 volts. So putting the filaments in series across 12v would make the dim-dip function a bit brighter which IMHO should be a slight advantage - but at the cost of 6 relays.

[electrokid]

Actually - thinking about it - if you want boxes - I can afford boxes (colours have no particular significance)

[KevR]

Can someone remind me again what the dim/dip actually does and whether it's of any practical use at all...?

[mat_fenwick]

It puts the dipped beams on at a lower brightness whenever ignition and sidelights are on. I think it was originally designed to stop people driving around with just sidelights on.

As to whether it's any use - personally I tend to drive around with headlights on most of the time, but this does have the potential to confuse people into thinking I'm flashing them if I go over a bump. So dim-dip is ideal in that respect. One of my biking mates also reckoned if I drove around with full dipped beams on, bikers with dipped headlights would be less visible. Not sure I buy that argument, but if you do that's another reason in favour of dim-dip.

[Defender110]

Can someone remind me again what the dim/dip actually does and whether it's of any practical use at all...?

"United Kingdom[edit]
UK regulations briefly required vehicles first used on or after 1 April 1987 to be equipped with a dim-dip device[20] or functionally dedicated daytime running lamps, except those vehicles type-approved to ECE Regulation 48 regarding installation of lighting equipment—this exception was made because ECE R48 did not require dim-dip or daytime running lights, and while countries signatory to the ECE Regulations are permitted to maintain their own national regulations as an option to the ECE regulations, they are not permitted to bar vehicles approved under the ECE regulations. The dim-dip system operated 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.[20]
The dim-dip lights were not intended for use as daytime running lights. Rather, they operated when the engine was running and the driver switched on the front position (parking) lamps. 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 low beam headlamps; 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.[21]
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.[20] 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."