I wanna rewire some things in my truck, and i wanted to know if it would be safe to use a key switch for certain things, like off road lights and things like that. And if not if there is a way to put a key switch in to lock the lights if it has not been turned or has the key in it.

 

Yes, if you do it right.

Because different devices in cars and trucks require different amps you should never power them directly from any switch, key or toggle style, running higher amp wires around metal car/truck parts is just asking for trouble in shorts and melted wires.

You use a Relay rated for the amps needed, and activate the relay with the switch.
Also less wiring is usually needed with a relay.

A relay has 4 connections total:
The coil has 2, when you pass power thru the coil it "pulls" relay "arm" closed, connecting the other 2 connections on the relay, this requires less than 1 amp to do, close to 1/2amp.
The Coil part is the voltage rating of a relay, a 12volt relay means coil will pull down the arm if 12volts are used

Other 2 connections are the Load, this is the amp rating of the relay, a 12volt/30amp relay can handle up to 30 amps passing thru these two Load connections.
A 12volt/60amp relay can handle up to 60amps.
Either would only need 1/2amp to close relay and pass those amps to a device.

One connection of the Load is usually a fused Battery wire large enough to handle the amps need for the device being powered.
The other Load connection goes to the "+" connection on the device, also using a large enough wire to handle the amps needed by the device.

Battery power is in the engine compartment and most added devices are on the outside of the vehicle, so good place to wire a relay.
Fused Battery power to relay Load, small jumper from this wire to either coil connection(for the 12volts)
Another wire from the other Load connection to the Lights.
Ground the Lights

So we have Load wiring done and we have 12volts at Coil, but no Ground for coil so it won't activate.
We run a small "Ground" wire from coil connection to inside the cab and to Key switch(or toggle).
Then a short jumper wire from key switch to cab ground.
When key is turned ON, the relay is grounded and closes, lights power up

 

Thanks. So i can do this with like a main switch right? Cause i wanna make it so i can turn them all one at once, with a main switch, but make sure they have there own, so i can turn off one of them if i dont need it

 

???

What lights are we talking about?

Stock head lights with added driving lights?

LED lights around outside of truck?

Interior added lights?

Describe what you want as the end result.


Keyed switch I was talking about looks like this one: http://www.oemsurplus911.com/calterm...tyswitches.htm
Look at 42050 / SS - 20

Maybe you are talking about using the Trucks key switch, so using a circuit that only has power when truck key is turned to RUN(on)?
Easy to do with a relay

 

I am adding alley lights and amber lights for work. And i wanna have them all in my center console. and they would each have there own switch. Something like this for each light.
But i wanna make it so i can turn all those switches on at once by leaving them at the ON position and having it controlled by this so i can turn the key, and all the lights would come on, then the ones i dont need i can just use that switch to turn it off.

 

So 3 on/off switches, 1 for each side light(alley light) and 1 for amber lights and then a Master keyed switch.

Do you want the on/off switches to be lit only when on is selected or back lit all the time to see where they are?

You might look at round switches that are lit, like these:
It is easier to drill a round hole than a square or rectangle hole when mounting switches

 

I would like to set it up so i can leave the switches on, when but have it so the Master key lets power to them so the lights come on. Cause i dont wanna have to flip every switch one at a time

 

I would run a larger fused power wire to the relays(location of your choice), this wire/fuse needs to handle the amp draw of all the lights.
It will connect to the Load connection on each relay, so 2 or 3 relays, however you want or need it to be hooked up, to divide the on/off of each light.

Connect other Load connection to its Light or Lights using large enough wire for that lights amp draw, you can also fuse this wire as well, if there is a short then you would only lose that light not all the lights if main fuse blew.
Ground the lights locally.

If you want to use lighted switches then Ground one coil connection on each relay locally.
Run smaller wire from each relays coil to the switches in the cab, this wire will just need to handle 1amp or less.

New Key switch in this case will provide the 12volt power to activate the relays(if light switch is on) this will be under 5amps(for up 5 relays) including switch's internal lights.
If you ran the main power wire to the Load direct from battery power then you have the choice of having the lights available with ignition key on only or any time.

Run 5amp fused wire to your new key switch from ignition key on power or 24/7 power
Run wire from new key switch to each light switch, it can be daisy chained from one switch to the next.
For the light in the switch to work you will need to ground the light bulb in the switch locally.

Turning new key switch on sends 12volts to light switches.
If on these switches pass that 12volts to the relay's coil, if coil is grounded then relay closes and passes high amp current to lights, if lights are grounded then they come on.

Can you do this with out the relays, of course you can.
Point of using relays is to minimize high amp wiring in the vehicle.

You could run two #2 gauge wires to a 300amp switch on the dash to activate the starter motor, but the starter relay is much safer for long term use.
Just because it is only 10-30amps doesn't make it safe to run those wires.

The fewer and shorter the high amp wiring is the better it is

 

Okay. Thanks a lot. And i am gonna use relays, people tell me it helps give the full power and there will be less voltage drop