The Fordson Tractor Pages Forum

I'm trying to decide how to wire up my repro side lights.

The holder from one of my original lights, sadly beyond repair, is shown below.

The bulb holder sits in a rubber mount inside the light and so is insulated from the body of the light. Note that the original bulb has a single filament, rated at 12V/6W, and two contacts at the bottom (see RH bulb in photo below). Thus one of the contacts, with the black/white wire, is attached to the surface of the tractor's wing serving as Ground.

Unlike modern bulbs, the metal body of the bulb does not form part of the circuit and is insulated from both contacts. Another point is that the two nubs on the side of the bulb are the same distance from the base, meaning that the bulb can be fitted in two positions 180degs apart.

The photo below shows the bulb from the repro sidelight (left) and original bulb (right):

Both bulbs have the same sized base, so both will physically fit in repro or original holders.

But the repro metal bulb holder is not insulated from the body of the light. Indeed the holder is pressed into the body of the light and is thus at Ground.

The repro bulb has two filaments rated at 21W/6W. Interestingly both filaments are attached to one of three wire posts inside the bulb. The repro bulb has two contacts at the bottom. It also has two nubs but, unlike most modern bulbs, both are the same distance from the base of the bulb meaning that the bulb can be fitted in two positions.

Question:
Why does the repro bulb have two filaments?

Do I ignore the 21W filament (which seems much too bright for a sidelight) and use just the 6W filament? Since the ground is via the metal body of the bulb, the other wire can be cut off and removed? Or is the 2nd filament in the repro bulb for a brake light, in case we chose to fit our dexta with brake lights?

Alternatively I could retain both wires in the repro holder, but fit an old style bulb having a single filament and insulated metal body. Note that if both wires are retained and a repro bulb is fitted, one of the two filaments will light up depending which position the bulb is fitted.

Has anyone wired up their repro lights, if so how?

Can the old style bulbs with insulated metal body be easily sourced?

TIA

Hi Ben,

What the repro lights have is provision for standard side marker / stop light bulbs. They have the common for the filaments as the body of the globe with one of the contacts being connected onto the stop light (21Watt) filament and the other connected onto the side light (5Watt) filament. These globes have offset side pins to prevent them being fitted backwards (otherwise you get very bright side lights an dim brake lights).

The other globe is a standard single filament side light globe. These are still a commonly available globe. The side pins on these are not offset as it doesn't mater which way around they go and they will not normally fit the offset pin socket. (Shear brute force and ignorance does overcome the not fit problem and I have seen many tail lights with the wrong globes in them.)

It is your choice as to how you wish to wire your lights, you could just wire the side light 5Watt fillament (earth is via the body of the light) and have the electrics work exactly like an original tractor, or you could add a brake switch and wire that onto the 21Watt filament as well and turn them into combination stop / side lights.

I hope this helps.

Regards, Frank.

Really intersting stuff mate. My own lights have 3 wires and this stumped me. Has anyone ever fitted brake lights?

I have just completed this exercise.

Personally I find single contact bulbs or fittings which earth through itself a right royal pain and highly unreliable.

A good fix :-

Remove the bulb holder from the repro unit and exchange it with a double contact insert from a commercial vehicle Rubberlite side marker lamp. This bulb holder is the same size, will fit into the repro unit, and has two screw fix terminals at the bottom for the wires. Fit a double contact 12v 5w bulb.

Easy to wire :-

Connect twin core cable to the bulb folder, pass it throught the conduiting and return it to the loom in front of the dash. Power supplied from the side lamp supply (Black) and then connect the other wire in the twin core to the Earth point with all the others (white/Black).

justjamiefarming wrote:I have just completed this exercise. Personally I find single contact bulbs or fittings which earth through itself a right royal pain and highly unreliable.

A good fix :-
Remove the bulb holder from the repro unit and exchange it with a double contact insert from a commercial vehicle Rubberlite side marker lamp. This bulb holder is the same size, will fit into the repro unit, and has two screw fix terminals at the bottom for the wires. Fit a double contact 12v 5w bulb.
Easy to wire :-
Connect twin core cable to the bulb folder, pass it throught the conduiting and return it to the loom in front of the dash. Power supplied from the side lamp supply (Black) and then connect the other wire in the twin core to the Earth point with all the others (white/Black).

I don't think it would be that easy to remove the bulb holder from my repro unit - it seems well jamed in, maybe even crimped. How did you get yours out? My repro unit does have twin contacts, so I'm tempted to leave it as is.

Where can you buy double contact bulbs?

I like your idea of running a separate earth wire to the lights. I was thinking of doing the same. Yesterday I collected my new wiring harness from Autosparks, who did a brilliant job fitting some different end fittings then braiding it up whilst I had a cup of tea. I also got some white/black wire for the extra earths. Surprisingly their harnesses are no more expensive than imports of dubious quality.

Have you any photos of your wiring?

You got your loom from Autosparks in the end then Ben, yes agreed, great quality and a great price!

russelm wrote:You got your loom from Autosparks in the end then Ben, yes agreed, great quality and a great price!

Yes, excellent service. It is surprising how many folk haven't heard of them, although they do make a lot of harnesses but mainly for cars.

Sorry, I didnt take a photo of the wiring.

As for the bulb holder:- I bought my repo units from A******e and the internal components were hideously cheap and nasty. The bulb older was just a push fit into a rubber outer jacket which is, in turn, a push fit into the unit. Therefore it was just a matter of a simple exchange of bulb holders.
Any automotive electicians or component suppliers will stock 12v double contacts bulbs.

(double contact rules every time! )

I have fitted brake lights to my dexta. used a small switch under the footplate connected to the brake shaft by a spring. gives not trouble and makes things alittle safer on main roads. only issue is that the brake lights are on when the handbrake is used. they get warm though because the lamps are not designed for such high output bulbs.
regards,
John

john.n wrote:I have fitted brake lights to my dexta. used a small switch under the footplate connected to the brake shaft by a spring. gives not trouble and makes things alittle safer on main roads. only issue is that the brake lights are on when the handbrake is used. they get warm though because the lamps are not designed for such high output bulbs.
regards,
John

Do you have any pics? what kind off switch/spring did you use?

Thanks w59d

i just used some things i had lying around. keep meaning to by one intended for a motor bike. type something along the lines of brake switch into ebay and you will find one. its all hidden under the footplate.
regads,
John

depending on the locaI regulations (so this is for Belgium only !):
Agricultural equipment (slower than 30km/hr) do not need braking lights
So I used the 2nd light to have direction indicators ! (the 21 W for the direction indicators and the 6W as driving light)

russelm wrote:You got your loom from Autosparks in the end then Ben, yes agreed, great quality and a great price!

Just discovered my Autosparks upper dash bulb holders are faulty - there's no internal thread so the bulbs won't stay in.

Discovered this after assembling the upper dash panel - grrrrrrr!

Autosparks have provided replacement holders but it's still a PITA.

Advice: Check all parts before assembly - I can't think why I didn't!!

I bought a brake switch from Auto Electrics (http://www.autoelectricsupplies.co.uk/ and fitted it to the underside of the LH footplate. I connected the pull shaft via a small tension spring to a Jubilee clip on the brake pedal shaft so I could adjust it. Has worked fine ever since (4 years). I wired it up to a distribution box on the back of the wing mounted toolbox where I also have wired up a Trailer 7 pin socket and a seperately switched auxilliary socket for my plough lamp or beacon.
I'll post some pic's WHEN it stops raining!!
I also used non-original sidelights with stop and indicator lamps as I took the view It was better to be safe on the road than to adhere to the original spec.
Cheers
Jerry

Just discovered my Autosparks upper dash bulb holders are faulty - there's no internal thread so the bulbs won't stay in.

Discovered this after assembling the upper dash panel - grrrrrrr!

Autosparks have provided replacement holders but it's still a PITA.

Advice: Check all parts before assembly - I can't think why I didn't!!

I had exactly the same problem.

Autosparks replaced them immediately and I sent them a polite communication outlining that such a quality piece of work is ruined by the use of such cheap components as these bulb holders.

Autosparks loom still a quality item though.

justjamiefarming wrote:Autosparks replaced them immediately and I sent them a polite communication outlining that such a quality piece of work is ruined by the use of such cheap components as these bulb holders.

Jamie,
Did they send you replacement bulb holders or a complete new warning light harness?
If the former, how did you attach the new holders?

They just sent the bulb holders, not the entire loom.

Because there is a shortage of space up there, I decided to inline twist and then solder the wires together and then cover them with a length of heat shrink sleeving.

(Dont forget to put the sleeving on first before joining the wires .)

Regards, Jamie