How connect DRL controller red and black wire to battery

Add more wiring

 

I would just peruse the wiring diagram (more info) and choose a sensible spot in the underhood fusebox that has the +12 volt supply that you need and with adequate capacity.

 

let me know if this helps you out.

Gen 3 Toyota Prius DRL always on Mod - black_jmyntrn

EDIT: its actually this link.
Wiring Diagram for Dual LED Switch Light Bar and DRL - black_jmyntrn

 

Hey I modded my DRLs to be always on exactly like you did in your first link.

But I wish to connect them to a switch to be turned off while camping.

The wiring diagram is confusing to me.

I have the switch, but I need an aftermarket relay?
Does the wire extend out through the lid of engine bay fuse box through the firewall into the cabin? Do I need to touch the wires attached to the DRLs in the bumper?

You also made a post about using a wireless remote control...

I’ve been trying to figure this out for months, and you’re clearly the genius here, I just need help understanding this in plain English... Thank you.

 

You need to understand how a relay works.

There are basically 2 circuits in the relay linked above. One circuit, which will have the switch on it, is the coil that opens or closes an internal switch in the relay using an electromagnetic field generated by the coil when current passes through it. The other circuit in the relay is the one wired between the power supply (usually a battery, in this case the fuse box 12v fuse) and the device you want to switch power to (DRLs).

The main purpose of using a relay is to avoid running the full current required by the load (DRLs), usually measured in amps, through the switch. The switch, then can just control the small amount of current required by the coil in the relay, usually measured in milliamps. The main switched circuit in the relay is also rated in how many amps of current it can handle.

Yes, typically you would want your switch in the cabin (dashboard), so you have to run wires through the firewall. That's another reason why you should use a relay, so the wires running through the firewall can be much thinner and carry only low amp current. This reduces the fire risk should a short circuit occur if the wires are compromised.

Of course fuses should also be used as another layer of safety, especially between the power source and the main load.

So to be clear, the switch goes between the power source and the coil on the relay, the other coil terminal is grounded to complete that circuit. Then the other terminals on the relay are wired between the power source and the load (DRLs), which ultimately need to be grounded to complete the circuit.

Posted via the PriusChat mobile app.

 

When you shop for relays, you need to get a relay with a proper coil specification, like 12V DC, in this case.

Also, the resting state of the switch in the relay, with no current flowing through the coil, is stated in the relay specifications as normally open (NO), or normally closed (NC).


Posted via the PriusChat mobile app.

 

I think I have a solution for you that'll be easy...need to write it up

 

Hey thanks for the help guys!

Xliderider, your super detailed explanation on the fog light post gave me the confidence to do this.

And Mr. Neutron, your website is amazing! Really inspiring.

I’ll be wiring a relay and switch with an inline fuse to my aftermarket side mirror puddle lights soon.


My main confusion here comes from the DRL wires specifically.


In the engine bay fuse box, instead of using an add-a-fuse leading into the pin where the OEM DRL relay used to be, I won’t use an add-a-fuse, and wire from where the OEM DRL relay was, to a new relay to pin 87?

This new relay is kept in the fuse box? And the wires will extend from under the fuse box lid, through the firewall?

Pin 30 leads to power, then 85 will lead to the switch.

I think I get it now, just would like clarification so I can do this cleanly! Thanks again!