How do you wire up spot lamp/foglights using a relay?

[little-ls]

i was watching wheeler dealers and on one of their episode they had a range rover, they had wired up some spot lights using a relay?
i know i would need a relay and wiring but has anyone got a diagram and also would any relay work? fwn

 

[porkpie700]

My foha micra had a relay for its fogs, it was well rotten & busted so i ditched it and piped them up to the full beam on the headlights. The relay had 4 wires conneted to it.
One was an earth to body.
One was spliced into the full beam wire on the drivers side headlamp.
One was a direct live to the battery.
The forth one connected to the + on the fogs.

So how it worked was;
When full beam was turned on the relay detected the power going to the headlamp and flipped a switch inside itself to connect the + wires on the fogs to the direct live from the battery, making them light up without drawing current from the headlamp circuit.

Hope that helps boyo (Y)

 

[little-ls]

Doh! missed an important question, would one relay do the job for both lights?

 

[porkpie700]

Well yeah, it's designed to do that. They wouldn't use just one if it couldn't do the job, and it feeds the fogs with a direct live, they can suck as much power as they want through that baby it won't hurt anything. (Y)

 

[pjg1979]

Usually each lamp takes about 5 amps each @ 12v or when the vehicle is running around 4 amps. Most relays are rated at 30 Amps which is sufficient.