I want to add some lights behind my grill and below my bumper, that flash with the signals when the headlights are off, and turn on, and flash off with the signals while running my headlights. I came up with the following wiring diagram.



Where S is the power for the turn signal, M is the power for the marker lights, and C is constant.

I is input, O is output, N is the neutral/default circuit, E is the circuit when the power is applied to the trigger T, and L is my load, or extra lights.

When my markers are off, power should flow from C through RelayA O-N, to I-E, dead-ending until my S energized the RelayB, allowing power to flow to my extra lights, L.

When my markers are on, power should flow from C through RelayA O-E, to I-N on RelayB, to my lights, and when S energizes Rb, cut the flow of power to the spare lights.

It took me several tries to get here, but I know someone is going to tell me there is a simpler way. These will all be LEDs, and I am planning on running about a dozen 6-diode lights.

I would imagine that the signal circuits are heavy enough to run a relay.

 

First... Here should be the diagram of the relays your using.

Second... So i'm clear, you want extra signal lights in the day time? Then rely on the factory lights when its dark.

I may suggest one 5 prong relay...You can see the 3 different setups.


I think a simple solution may be to switch the grounds when you turn on the headlights. Doing so with a simple 4 prong relay where 30 and 87 are normally closed. When power is added to 85 from the headlights and connects to ground 86, this will open(cut) the circuit. Since they are LEDs and your planing on having more than one circuit(power source), switching the grounds may be the best way to go. Otherwise in order to have them flash independently from each other, with your turn signals, you would have to use excessive relays.
Again this is only a suggestion. I usually try and think of 2 or 3 ways to do it. A LOT can be done, simple and complex. Often simple works best. I work with a lot of circuitry and dealing with relays and ways to use them.

 

I want them to flash with the signals in the daytime, then at night have them light with the markers, and when the signal flashes on, they flash off, opposite the signal. I couldn't come up with a way to do it without two relays.

 

Um, you just need to splice into the wiring for the lights on your front fenders. They alternate from the ones on the grill. The only tricky part is that you have to complete the circuit. They won't work if you pull one wire. It has to go through your lights. i don't really understand your wiring diagram completely. (I might be re-inventing the wheel here) I didn't use relays though. It would be the "right" way to do it, but I run 4 LED lights no prob. this way on my truck.

 

I understand what you mean now. And agree with schamran, But like this way better. Using the relay above(but normally closed). Take the hot wire from the side markers to the one leg of the constantly closed circuit 30. Then on the return side 87, run the positive side of the LED. Complete the LED circuit to Ground using the chassie. This will ensure the leds will only lite when running lights are on. Next run a power wire from the turn signal positive on the front to the magnet 85 of the relay and complete the connection to ground 86 on the other side.

Edit-sorry for the confusing way my brain works...still confusing after edit, sorry.

 

nope, not what i meant. If you were to run one light, in theory, splice each wire from the fender light to each terminal of the grill light There's 2 terminals on each light. No ground. Just remember that LEDs are polar. It is a really goofy circuit. I don't understand why it works, but I understand how, if that makes sense.

 

check my edit... I understand how DC circuits work, you can light a bulb alone + to - or in series, + to + to +.... to - all circuits on a dc system need to goto a ground in order to work.

 

I made a diagram in paint. HAHA if u can understand im tired.

 

I'm just telling you what i did, and it worked. If it needs to be grounded, then there is a ground on the second wire of the marker light in the fender. I think that would work better than grounding to the chassis because that is one more ground connection to go bad.