Need help getting aux lights to switch off when headlights activate using relay.

SOLVED!!


I have some aux lights that I want to use as daytime running lights. But they are too bright to use at night so I want them to switch off when I turn on the headlights. Do I need to use a 5 pin relay for this? Or will a 4 pin work? Trying to figure out if I need to wire it positively or negatively. Never wired anything up negatively before but I think that's how I need it if I'm thinking straight. I have the 85,86 and 30 pins understood. But how do I wire it to pin 87/87a? I am thinking that pin 87a should be wired postive to the lights. And 87 left blank. That way when the headlights turn on 87a loses power but switches it over to 87 which wouldn't be wired to anything. But it seems like there's and easier way to do this possibly through negative switching.. Isn't there a way to just wore it up so that the light loses ground as the headlights turn on?

 

If I understand you correctly, you only wish to use the aux. lights in combination with the DRL's? Or do you wish to retain the ability to switch them on at anytime?

Option 1: Only with the DRL's

This setup will make your lights turn on ONLY with the DRL's and off whenever the DRL's are off.

You can use a normal 4 pin relay.

Relay Pin Setup:

30 - Connection to aux. lights. (Make sure you fuse it)
87 - +12v from battery
85 - +12v from DRL's (spliced)
86 - Ground

Option 2: With DRL's or Anytime

This setup will allow your lights to be turned on whether the DRL's are on or off.

You will need a 5 pin relay and a normal two position (on-off) switch.

Relay Pin Setup:

30 - Connection to aux. lights. (Make sure you fuse it)
87 - +12v from battery (For DRL's)
87a - +12v from battery (For Anytime)
85 - +12v from DRL's (spliced)
86 - Ground

Place the On/Off switch on the +12v battery lead going to 87a to allow the lights to be turned on when the DRL's are off. Normally, I prefer to place a switch on the grounds, but these relays are either: 1 input to 2 separate outputs or 2 separate inputs to 1 output.



If anyone sees a change that is needed in my circuits, feel free to correct them.

 

I want to have my aux lights on ALL the time, until it gets dark then I want them to automatically switch off when the headlights turn on. I was thinking;
30- constant +12v power
86- ground
85- +12v signal wire splice into headlight relay or wire sonehwere.
87a-+12v power to lights
87- empty.

So that the lights turn off only when the headlights turn on.

 

I don't happen to own a Tacoma, but doesn't the DRL's turn on automatically with the ignition, but turn off once the headlights are turned on?

If that is the case, then my Option 1 and your circuit plans are exactly the same (yours retains the ability to upgrade it to my Option 2 if you want to be able to use your aux lights in conjunction with your headlights).

Just make sure you place an in-line fuse somewhere on the +12v from the battery for the aux lights in case they ever happen to short out.

 

Actually the drl's do not come on with ignition. It's a three position headlight switch. 1st is drl then 2nd is headlights. And of course the high beam u flick it forward.. But no they don't turn off when headlights come on. That was my problem or I would have wired it to the drls using a 4 pin relay. I would like the option to turn them on with the headlights too but I'll figure that out later. Right now I have too many lights as is and they will flicker with these extra ones and they have been disconnected for a while because of that. So I figured I could just wire them up like this until I get my second battery setup.
And I also have a blue sea fuse box installed for everything

Anyways I'm pretty sure I have this figured out now that I've thought about it and did some testing on the switch. But it ended up raining so I didn't get a chance to wire it up

 

Well in that case, your circuit will work exactly how you want it to. Good luck with install, should go smoothly due to your previous wiring.

 

Well I just got done wiring it all up. Turns out I had to actually run TWO relays just for those lights. I wired it up to the blue sea fuse block using the 5 pin relay. But I realized that my block was wired to the battery with constant 12v so that meant they would stay on even with the truck off. After I scratched my head for a minute I realized I had to wire an additional 4 pin relay using a signal wire spliced into the drl's so that it would turn on when they did.
And these lights are actually rigid srq ambers mounted on my hood. Using them as daytime running lights. Probly be too bright at night to use as running lights. Worked out quite nicely this way!

 

Well we both forgot that little aspect didn't we?

What you could have done instead of using the signal wire from the DRL's is use a +12v from the fuse box that is only hot while the ignition is on/running. But then you'd have the issue that they'd be on if you put your truck in aux.

Throw up some photos of the completed build!

 

Here's a little more detailed writeup on how I did it. In case anyone needs this in the future.
4pin relay;
30- +12v to blue sea fuse box (or battery)
85- -ground to blue sea fuse box
86- + 12v spliced to drl wiring
87- +12v to pin 30 on 5 pin relay

5pin relay;
85- -ground to blue sea fuse box(could be combined to the same ground on other relay as well to be one connection instead of two.)
86- to headlight bulb connector positive side.(which the connector on mine on passenger side was unused from hid/projector kit. Or could be tapped into headlight relay.)
87a- to aux lights
87- empty