Which of the 3 ignition switch wires can I use to power a relay?Which wire does what?

So, I need power for my 24V back-up camera, and I want it to turn on when vehicle is running and turn off when I stop the engine.

Which wire is live during the drive? Is it safe to run a "Y" connector through that wire to a relay that will turn on and off when I kill the engine?

My desire is to run a relay to turn its own 24 Volt circuit that will power my camera, CB/SSB radio, and double DIN vehicle radio. When the vehicle is on, I want the relay to activate, and when I kill the engine I want the relay to deactivate. I'm hoping a 15 amp circuit will be enough. I also have a full time power inverter for 12 Volts, so I might want to run 2 relays.

I need to know which wire to use, and I need to know if using that wire is safe. I also guess I need to know how many amps the "Y" connector needs to be rated for, or what gauge wires it should have.

Thanks,

T

At the STOP RUN START switch it would be the 458 # lead. (wire tag stamped 458 supplying 28 volts in the RUN position.

FUSE IT for your low current needs to your camera or slave relay. I wouldn't draw more than 2 or 3 amps MAX.

If your pop-in wires off & on, pay attention or that will be a new thread or starter.

Time to trade-in one of those Tesla's for the TM's...... LOL, CAMO

Could do like for the reverse lights circuit, pull from the hot side of the horn. Power will be on anytime the lights are on for running or headlights. Means no reverse camera if you don't turn on the lights or have it in blackout mode, though unless it's a night vision camera I don't see how that would be an issue.

That's a good idea. How about a switch called "accessories" maybe with a light on it. Turn on the extra stuff when you need it. Like the head light switch... have to remember to turn it off.

Many bright ideas, CAMO

I always wire BU lights on a separate switch, this way they serve as rear facing utility lights I can use and keep on and nit have to be required to put the truck in reverse to get rear lights.

I assume that you are looking to use the "spliced in" wire as the control wire for a relay, that when closed will carry the actual load of your accessories. For the control wire to the relay, you could use either a #14 or #16 gauge wire. Either would be more than enough to power the relay solenoid. For the load wire from your +12 vdc supply to the relay contact, you would probably want to use a #10 stranded wire. I then went from the output contact on the relay to a 6 circuit fuse block with another #10 wire. For each circuit out of the fuse block, I ran #14 wires to the various accessories. You can get small 12 volt or 24 volt auto relays, with contacts rated for 40 amps on e_b*** for about $5. I have a 12 V and a 24 V one in my truck. When I select either the 12 or 24 switch in the cab, the appropriate relay contacts close and I have power to the selected fuse block (either the 24 or the 12).

Retiredwarhorses said:

I always wire BU lights on a separate switch, this way they serve as rear facing utility lights I can use and keep on and nit have to be required to put the truck in reverse to get rear lights.

Click to expand...

I did the same, but also hooked them to the trans switch - makes it nice so they automatically come on with reverse, but I have them also switched so I can use for working behind the truck. Have to remember to take it out of R when I park it - because the way I have it they would stay lit and run the battery down.

Ordered a few y connectors and male and female packaged connectors. When they arrive I will steal power from the horn, as suggested. I want the rear camera always on. Gonna mount hidden behind a predrilled hole in the rear body. The camera will steal power from the rear light once I swap to LED. (I always drive with lights on.

Once that is done I guess it is off to the next issue.