Driving lights wired to high beams?

[adworden]

I have a set (2) of 9-light LED driving lights for my 2007 Edge. My questions  are: can I wire them directly to the high beams, or do I have to go with relays, switches, etc.? Where would I find a "hot" wire to use? Thanks.

[Gadgetjq]

If you tap into your high beam circuit you'll need a relay.  If you connect directly to a switch and to a circuit in the fuse box probably not (but it's always a good idea).  Here's why. 

The high beam circuit is already fused for the expected load and for the size of wire used in the circuit.  An example of the lights you're describing come up online as 50 watts (which seems like a lot for 9 leds but it's the number they cite so I'm running with it).  That's almost 4 amps each, 8 amps for the pair which is adding quite a bit to an existing circuit and certainly erasing any head room for the fuse.  If you use a relay though, it will only use a couple of amps and you 'can' connect it to your high beam wiring.  You'd just connect the positive side of the lights to the relay and the relay to the under hood fuse box.  If yours is like my Gen2 there are unused fuse slots that should have no problem with a 10 amp (the lights 8 amp plus a cushion) for your leds. 

If you choose to add your own switch so your strips can be used independently of the high beam your circuit would be similar except you'd connect the relay to one fuse under hood (switched on with the engine so you can't inadvertently leave your lights on) fuse and the lights to another (switched or unswitched wouldn't matter since the relay is acting as your safety switch. You'd add your manual (cabin) switch in the line between the relay and the fuse.

There are many circuit diagrams online showing how a relay is connected but it's very simple.  The relay is just an automatic (as opposed to manual) switch that's activated when power is applied.  A latch closes allowing the higher amperage (your lights) to pass through. 

Cheers!

Edited April 30, 2020 by Gadgetjq