Sambora8080 · Dec 13, 2014

Hi all i am fitting some DRL lights to my defender 90

The kit i have is very easy to wire up to a standard car where the battery is under the bonnet.

However on the td5 90 the battery is under the passenger seat as you know. Due to the length of the supplied wiring loom it is designed to all be located under the bonnet area as it needs to be close to the sidelights to pick up a 12v signal from them aswell.

I was wondering rather than the cables being extended to reach under the seat can anyone think of a handy place closer to the lights that i could connect the wiring too.

Obviously it has to be a permanent 12v supply just like it would if you connected directly to battery and it will use a 12v signal from the sidelights to enable the dimming mode for night time driving.

Im presuming the lights will switch on via the relay control module when the battery voltage rises above 12volts (as the engine starts the alternator kicks in providing a rise in voltage as it charges the battery)

If theres not really an easier way then its no mithor running back to the battery under the seat just thought id see if people had done it any other way.

fanatic · Dec 13, 2014

Possibly heavy cable on alt battery stud to sub fuse box

mattlumley · Dec 13, 2014

Would they not be powered from an ignition live feeed? Thats how i have installed them on more modern cars.

trax · Dec 13, 2014

mattlumley said:
Would they not be powered from an ignition live feeed? Thats how i have installed them on more modern cars.

you need to calculate max current for the entire circuit and make sure it's within limits. if not then you could a leccy fire, depending on how you fitted them

mattlumley · Dec 13, 2014

Thats true and i have done. In my corsa ive fitted several additional lights/power points etc to add some missing functionality to a very basic car. Anything additional goes through a seperare fuse board in the boot as well.

trax · Dec 13, 2014

mattlumley said:
Thats true and i have done. In my corsa ive fitted several additional lights/power points etc to add some missing functionality to a very basic car. Anything additional goes through a seperare fuse board in the boot as well.

generally, if you are talking higher current draws then it's best to use a relay in the engine comp and a low current trigger in the interior. fuses as normal. this keeps the higher stuff away from the interior combustible materials if it ever burnt out/shorted/etc

mattlumley · Dec 13, 2014

Not heard of that before, the stuff ive wired to the ignition live is all low current draw anyway so should be ok. How does your method work if you dont mind me asking?

mick the builder · Dec 13, 2014

Excuse my ignorance but if you need to attach to battery and the loom wont reach, can you not bring a cable from the battery to the loom and attach via an inline fuse in the engine bay

Sambora8080 · Dec 13, 2014

I see there is quite a lot of points being mentioned here.

For the record the DRL lights are led so they dont even draw 1 amp!

And yes you would assume that you would pick up an ignition feed.

HOWEVER as i mentioned in the post you connect directly to the battery with these lights according to their instructions.

The clever relay module must recognise the engine is running by measuring a difference in battery voltage. ( E.g as the alternator is running battery voltage jumps up to about 14.8volts)

and there is already an inline fuse fitted to the harness.

So going back to my original question is there a closer permanent 12volt feed i can pick up. If not as i said before its not that big a deal extending the wires to the battery.

Its just when electrics are concerned the less connections you can have on a circuit the better. i wanted to avoid having to extend wires as this creates a weakness in the circuit.

I was thinking of perhaps picking up a feed from the alternator as this is connected to the battery.

trax · Dec 13, 2014

mattlumley said:
Not heard of that before, the stuff ive wired to the ignition live is all low current draw anyway so should be ok. How does your method work if you dont mind me asking?

it's just a normal relay job. you use a fused wire from the fusebox to a switch(whatever) going to the relay (200mA). this activates the heavy duty wire and fuse in the engine bay.

Sambora8080 said:
I see there is quite a lot of points being mentioned here.

For the record the DRL lights are led so they dont even draw 1 amp!

And yes you would assume that you would pick up an ignition feed.

HOWEVER as i mentioned in the post you connect directly to the battery with these lights according to their instructions.

The clever relay module must recognise the engine is running by measuring a difference in battery voltage. ( E.g as the alternator is running battery voltage jumps up to about 14.8volts)

and there is already an inline fuse fitted to the harness.

So going back to my original question is there a closer permanent 12volt feed i can pick up. If not as i said before its not that big a deal extending the wires to the battery.

Its just when electrics are concerned the less connections you can have on a circuit the better. i wanted to avoid having to extend wires as this creates a weakness in the circuit.

I was thinking of perhaps picking up a feed from the alternator as this is connected to the battery.

starter stud is the norm as it's a direct thick cable to the battery. alt will go to that stud.

jamesa · Dec 9, 2019

Ive just bought these:

https://www.sp-4x4.com/7_LED_HEADLGIHTS_FOR_DEFENDER_BLACK_p/md-j002.htm

and am having the same problem with finding a 12v source. How did it go? I've seen it recomended that you attach them to the sidelight with a SPDT relay so that the DRL switches off at night (required as they are too bright to be road legal?).

Sambora8080

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fanatic

RESPECT IS EARNED, BEATINGS ARE FREE ;-)

mattlumley

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trax

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mattlumley

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trax

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mattlumley

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mick the builder

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Sambora8080

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trax

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jamesa

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