pianomana440
Member
How easy is it to wire 2 work lights above the back 1/4 windows on to a separate switch on the dash? How would you do it?
dag019
Well-Known Member
I would say very easy, it is one of the first jobs that I did on my 110. I also used a three way switch so that i had the choice of on/off/reverse.
You would need a suitable relay, some twin core wiring, some spade connectors and a pair of work lights.
You do not say what age defender you have, if it is a newer one I believe there are auxiliary lighting kits available that plug directly into the existing loom, if it is an older one (as I am familiar with) this is the process I followed.
You can pick up a permanent 12v feed behind the centre dash panel from the brown or purple wire (wire colour from memory will confirm and update). Connect this to the input of the switch and connect the output of the switch to the relay. If you use a three way switch the second input on the three way switch wants to come from the reveres light switch on the back of the gear box.
Once the relay is connected to earth this will complete the switching loop of the circuit so when you operate the dash switch/select reveres gear and the reveres switch is operated, the relay switches and gives a live feed.
For the second loop of the circuit, to connect the work lights up to the relay, make a fused live connection to the relay either direct from the battery or from the back of the starter motor, this gives power to the relay.
Using the twin core cable connect one core to the relay and one core to the earth, run this through the dash, up the windscreen pillar behind the plastic trim, along the gutter of the roof to the rear of the vehicle. This then gives you power and earth to connect your roof light to.
See diagram below pulled from google.
You would need a suitable relay, some twin core wiring, some spade connectors and a pair of work lights.
You do not say what age defender you have, if it is a newer one I believe there are auxiliary lighting kits available that plug directly into the existing loom, if it is an older one (as I am familiar with) this is the process I followed.
You can pick up a permanent 12v feed behind the centre dash panel from the brown or purple wire (wire colour from memory will confirm and update). Connect this to the input of the switch and connect the output of the switch to the relay. If you use a three way switch the second input on the three way switch wants to come from the reveres light switch on the back of the gear box.
Once the relay is connected to earth this will complete the switching loop of the circuit so when you operate the dash switch/select reveres gear and the reveres switch is operated, the relay switches and gives a live feed.
For the second loop of the circuit, to connect the work lights up to the relay, make a fused live connection to the relay either direct from the battery or from the back of the starter motor, this gives power to the relay.
Using the twin core cable connect one core to the relay and one core to the earth, run this through the dash, up the windscreen pillar behind the plastic trim, along the gutter of the roof to the rear of the vehicle. This then gives you power and earth to connect your roof light to.
See diagram below pulled from google.
pianomana440
Member
pianomana440
Member
Thank you for your reply. It’s a 2003 Td5.
dag019
Well-Known Member
That may be different, the basic principle will be the same, and the relay wiring will be the same, but where to pick up a 12v feed in the dash may be different. You will have to wait for someone with more experience with newer models comes along.
mick 1986
Well-Known Member
I have to disagree there. It’s not safer to switch the earth at all, it will mean the circuit is live all the way through to the switch, permanently. Switching the live means only the feed to the switch is live permanently, not the rest of the circuit.
I agree with the cable advice though. Make sure you work out the working current of the circuit, add a little for diversity, and go from there.
dag019
Well-Known Member
I would agree with the above, you want as little of the circuit live as possible when not in use.
nobber
Well-Known Member
Its safer because when a ground goes to ground nothing happens, but when a live goes to ground things melt. So, from relay to switch to ground, relay being close to the battery, switch being on the dash, you have nothing in between except a ground wire, if it goes to ground before the switch (broken wire) your accessory may light up of blink, but nothing melts.
If you look at both these scenarios, pulling the switch will have two very different results. The think about the cable run from a Defenders battery box to the dash, mine runs down and outside the vehicle. Lots of things get earth switched these days.
If you look at both these scenarios, pulling the switch will have two very different results. The think about the cable run from a Defenders battery box to the dash, mine runs down and outside the vehicle. Lots of things get earth switched these days.
mick 1986
Well-Known Member
Both of them scenarios you have mentioned assume no fuse is present, so again that’s wrong. The “ground wire”, as you have called it, will still have +12V DC potential on it, as it hasn’t passed through a load. Draw a full circuit diagram of what you are trying to say.
Regardless of where a switch is placed in a series circuit, the current passing through the switch is the same, Kirchhoff’s first law.
mick 1986
Well-Known Member
I have just looked at it again, and think I understand what your saying now.
Put the relay in the battery box, fused live from the battery, through relay coil wiring, out on an “earth wire” up to a dash switch that switches to earth? Thus when the switch is switched, it connects the coil to earth. Is that what you meant originally?
dag019
Well-Known Member
That was my understanding, you are switching the relay earth, I can see how that would potentially be less risk as if it shorts out the circuit just switches on, the relay activates and the lights illuminate. Whereas if the live shorts out you could get a very high draw through the short, but that is why the circuit needs to be fused so the fuse blows preventing the draw on a short circuit.
Switching the earth also means you cannot (with my basic electrical knowledge) easily link it up to the reversing light switch to come on automatically with the reverse lights.
nobber
Well-Known Member
Yes, you want the relay close to the battery and aux fuse box, I would always put them in the battery box, you could put them in the cab fuse box but I would rather run a bus in the battery box or a distribution fuse box with one live feed in, It just keeps it all simple and safe and easy to fault find if something goes wrong.
dag019
Well-Known Member
The reverse light must be a live feed as I have mine set to switch the live side of the relay. But it is a long time since I did it, I will check the wiring diagram.
nobber
Well-Known Member
I cant remember if it has one or two wires going to it, perhaps I am thing about the diff lock warning lamp switch, or something completely different.
dag019
Well-Known Member
Diff light switch has two wires one in and one that then earths to a bolt on the gearbox. (I know that one as have taken transfer box out several times this year)
The reverse has two wires I think both going back into the loom.
edit: found the wiring diagram. It is a live feed on the reverse switch. And earths through the lights
