Outer Limits 4x4 Board

could some1 please tell me the easiest way to wire up a spotlight(just 1) for use as a reverse light, it sits under tray and am pretty sure its a 100w work light. it has 2 wires coming out of it if that helps.
ive done a search and came back more confused.
the easiest way possible as ive been told im colour blind to red and green, which i dont beleive as i know those colours when i see them.
anyway, let me know what i need to buy, eg, wires, fuses, etc.
please dumb it down for me.
thankyou

Okay, well, it's not too hard but to do it properly you will need to run one power wire from your battery as the standard reverse light wiring is not designed to handle a spotlight.

You will need red wire, black wire (or choose your own colours but do use two), an inline fuse, a typical automotive relay, and a relay base.

Then find the nearest stock reversing light and the wires that go into it.

What you are going to do is tap into the existing reverse light wires and use these to activate the relay. The relay will then act like a switch to turn the spotlight on and off.

To understand the relay: it has four wires. One wire comes from the battery for power. One wire goes to the reverse light to light it up. And two more wires turn the relay on or off.

The first job is to find a spot for the relay that is close to your reversing spotlight but safe from getting wet, dirty, etc. Mount it in place.

Tap into the two wires that run the stock reverse light and connect them to terminals 85 and 86 of the relay.

Run a wire all the way from the battery +ve terminal to terminal 30 of the relay. Include your inline fuse as close to the battery as possible.

Run a wire from the relay's terminal 87 to your reversing spotlight's +ve wire.

Then finally run a black wire from your reversing spotlight's -ve wire to the chassis/body/ground. You will find grounds nearby for the indicators, reverse lights, etc, or even for the towbar plug.


Here is a relay base: http://www.dse.com.au/cgi-bin/dse.store ... View/P8036

30A relay top suit (more than enough) from the same place, supercheap or wherever: http://www.dse.com.au/cgi-bin/dse.store ... View/P8035

Inline fuse, connectors to tap into the reverse light wires, etc, all available from supercheap or similar.

The other thing though is that a generic "spotlight wiring kit" will do the job too, instead of using high beam to trip the relay you use a reverse lamp. eg: http://cgi.ebay.com.au/FOG-SPOT-LED-LIG ... 2c504736fb

Very well explained. Thank you as i intend to do the same.

Are they legal like this without a switch in the cab like spotlights?

I am not sure on the legality. I think the rule was that they can't be wired to come on with the reverse lights, they have to be on a separate switch and you have to call them a "work light". But it might be the other way around!

thankyou very much chimp. much appreciated
one question though, what size or amp. wires should i use, what amp. inline fuse should i use.
thanks again

DUDELUX wrote:thankyou very much chimp. much appreciated
one question though, what size or amp. wires should i use, what amp. inline fuse should i use.
thanks again

Different people will tell you different things on wire size because it's a compromise that weighs up cost, ease of routing the wire, and how much voltage drop (which means slightly dimmer light) you can accept.

A 10A fuse and even fairly light wire such as 2.5 sq mm wire would probably do the job for one spotlight. I would go with maybe 4.5 sqmm wire but some people would say that is overkill for a single spotlight.

Beware as automotive cable sizes are fairly dodgy and it is hard to tell what you're getting from the label sometimes. Real 4.5 sqmm wire has a diameter of 2.9mm INSIDE the insulation. That is, the actual copper core is 2.9mm across for a total area of 4.5 square mm. Some auto cable is sold based on the total area including the insulation, which is basically stupid.

You should only need a 10A fuse for a single 100W spot light but if you use 4.5sqmm cable you could have a 20A fuse or something like that.

Fundamentally, the fuse is there to protect the wire - the fuse rating should be below the current rating of the wire.

A 100W spotlight should draw somewhere around 8A. Theoretically, a 1 sq mm cable is sufficient, but you'll get larger voltage drop - so, as the chimp suggested, something like 2.5 sq mm (copper size - not copper + insulation) will have more than enough capacity. On that size cable, I would use a 10A or 15A fuse.

thanks guys, youve been a massive help to you