wire up a rear light

[rob01]

I have read some of the answers to the reversing light set up but still am confused.
1. All I want to do is wire up a rear light.
2 I want to run it off my second battery.
3. I want an on off switch on the dash.
4. I want a relay
5. I just want to run the light from the switch ON or OFF

WHAT I HAVE DONE!

1. Mounted rear light.
2. Run a 2 wire harness from lights at rear to engine bay. one is power the other is earth or negative.
3.I have run a 2 wire harness through the firewall.
4. I have a Narva relay with 2 x 87 pins, 1 x 30 pin, 1 x 86 pin and 1 x 85 pin.
5. I have an in line fuse box with 20 amp fuse.

THE WAY I FIGURE IT IS

1. TERMINAL 85 OF THE RELAY GETS WIRED TO EARTH ON THE BODY.
2. TERMINAL 30 GETS WIRED TO THE POSITIVE TERMINAL OF MY AUXILIARY BATTERY THROUGH IN LOINE FUSE, 20AMP?

WHAT I DONT GET

1. WHAT RELAY TERMINAL GOES TO THE SWITCH IN THE CAR?
2. WHAT WIRE GOES TO THE SECOND TERMINAL OF THE IN CAR ON OFF SWITCH?
3.DOES THE SWITCH NEED POWER OF SOME SORT AND F SO WHY CANT I RUN IT TO THE BATTERY (PEOPLE TALK ABOUT ACCESSORIES WIRE, RATHER NOT)
3. THE TWO WIRES COMING FROM THE REAR LIGHT:
A) WHERE DOES THE POSITIVE GO?
B) WHERE DOES THE EARTH OR POSITIVE WIRE GO TO?

THE SWITCH I WOULD LIKE TO USE IS JUST A SIMPLE ON OFF LIKE MY DRIVING LIGHTS.

None of the schematics diagrams I have found on this site cover just and ON/OFF 2 way switch.

I would appreciate someones help please.

[crispy]

OK i'll have a stab at this

1. Run a wire from 86 to the switch in the cab
2. a source of 12v as the trigger for the relay for the way you have it set up, otherwise you could set it up a bit differently and switch a ground as the trigger.
3. As above, you could run it straight from the battery, people use acc 12v so its only on with the key and cant get left on i guess
4. the positive of what? for the light? then it goes to the 87 pin.
5. the earth wire of the light goes to ground

[rob01]

Thanks Crispy, that helps heaps, will see how I go.

[rob01]

Crispy, well thanks for that it works fine after initiateing your directions and thats saying something as I have got to be the worst aouto electrician type on the planet.

Bob

[crispy]

No worries, glad it worked...lol