Need help wiring relay to cut power when activated

Sorry for the long title, my attempt at explaining this example is:
I'm getting a set of Morimoto LED DTRLs and would like to have some sort of automation built in that will turn them off when the headlights are turned on.

Originally I thought to run these on their own switch in the cabin, but that will still leave the human element present to screw something up (maybe leave them on forever).

Is this even possible to do in a simple solution? Or is it more complicated than I'm thinking? Please also note I'm an electrical idiot. I wired my blue sea fuse block to the LED bars, but that's a simple one-relay-per-light set up.

 

You want these to turn off when the headlights are on? Probably easiest with an SPST relay with a NC - normally closed contact. Then have the relay trigger sourced from power to the headlights... Which would open the contacts to your fogs and shut them off when the headlights turn on. That would work assuming you have done a fog light mod so the fogs can be on when your headlights are not on.

Hope that makes sense.

 

this is very easy. 2 relays needed

wire your DRL's as you would a normal LED set up with a relay.

1st relay - DRL's
pin #87 - fused power wire from a switch source.
Pin #30 - to the DRL's
PIn #86 - power from a switched source
Pin #85 - wired directly to pin #87A on the second Relay

2nd relay
pin #87A - direct wire from pin 85 from first relay
pin# 30 - wired to ground
pin #85 - wired to ground
pin #86 - wired to the positive wire on the headlight circuit. you actually need to consider running a wire from the highs and lows to that relay. you will need to diode isolate each one also. prevents back feeding of power between wires.

Leave pin #87 unattached/capped off

the second relay when activated, controls the ground side of the first relay by disconnecting the ground.

 

thanks for the replies... now to pick up a few relays to test

 

I did something similar but wired it differently.

IIRC;

1st relay:
30-wired to battery
85-ground
86-spliced into factory dtrl wire
87-wired to pin 30 on 2nd relay

2nd relay:
30-wired to pin 87 on 1st relay
85-ground
86-wired to + from headlight circuit
87-capped off
87a- to lights being added

The first relay activates when the trucks dtrl are turned on, which activates the second relay at the same time. Then when the headlights are turned on, the second relay switches 87a off and powers 87. But 87 is left blank so nothing to power. It means the relays are constantly on, but I havent had an issue. Not sure how the above mentioned circuit works exactly, this is just how I did mine.

 

Thanks Harlan...

Look what just came out from TRS: http://www.theretrofitsource.com/led-lighting/morimoto-xchange-switchback-drivers.html#.VOdZiPnF_To

 

I don't think those would work like you want them to in your situation straight out the box, you would still have to add a second relay...

but using one of those, you could gain the "switchback" feature to what you are doing.

 

Just picked up the box from TRS and I can get one side to work. So simple but I'm banging my head against the wall

 

According to the description it should work either way. for drls or for switchback function. But I probably wouldn't be using these for any kind of high power accessories. Such as light bars. Only for led dtrl like you want to use them for.

"Daytime Running Lights: Simply connect the [9006 female] DRL-output to your Angel Eyes, LED DRLs, (or whatever else you want). Then feed a constant 12V into the white/black wires and tap into your low beam circuit with the yellow input wire. When the car turns on, so will your DRL's. When you turn the headlights on, the DRL's will automatically shut off."

 

Actually, shouldn't a single 5 pin relay work? Just wire the headlight power to the activating switch like mentioned in post 2!?

30-power from factory dtrl wire (tap into wire or use add a circuit from dtrl fuse)
85-ground
86-headlight +
87-capped off
87a- led dtrls

Led dtrls don't need that much power and can run off your factory wiring. There's no need to pull power directly from battery using two relays. I only did two relays because I was powering some rigid srq amber light bars as dtrl's and wanted direct 12v from battery through a separate relay.

 

Would I need a second relay to be able to put a switch somewhere in there? For example, have a spst switch in cab to turn on and off the halos whenever I want, but still have the halo turn off when headlights are on?

 

Pretty much exactly what I was thinking to comment on. Nice drawing. Only one thing you would need to do: Put a diode on the circuit from the add-a-circuit fuse to terminal 86 of the relay. The reason for this is simple if you look at your wiring diagram. The high beam and low beam both share a common ground in the bulb. Without a diode it is possible for power from the high beam to "backfeed" into the low beam fused circuit through the low beam filament. This would attempt to energize the relay, causing possible erratic operation.

 

Hmm.. I wonder if this was my issue I was having recently. I saw someone suggest the samething but, I've had my lights wired up for quite some time this way. Specifically my led lift bars. To turn on with high beams. never had an issue until water got in one relay and it started hyper flashing, erratically, with my little amber bars that i mentioned earlier that I use as dtrls which switch off when headlights come on. Other white bars are wired similarly but with a single 4pin relay. Well just recently my led cannons started hyper flashing when deactivated. even with the headlights off. So does this sound like a short caused by water in this other relay as well or maybe this feedback you're speaking of? If that makes any sense.. I'll have to write up some diagrams. But being 1st gen I have the negatively switched headlights so I have 85 and 86 tied into my h4 harness to work properly.. probly shoulda stated this in another thread but oh well..

 

No light bars here, just an LED halo in each headlight that I'm trying to get to turn off when my headlights switch on.

I have a Y'd off wire coming off of my existing relay to power my halos right now. With this set up both halos work with the manual switch I put in the cab. When I put the TRS controller inline, only my driver's side halo lights up. (This is the side closer to the relay)

 

No idea why, but this is working now. I tried connecting the controller to the passenger side first, and it worked.

 

So you have battery to relay, relay to TRS module that turns the halo off when headlight is switched on, module to halos, and a switch inside to turn it on and off whenever?

 

Battery to relay
Relay to dashboard switch
Relay Y'd off to TRS module
Module to halos

I had the switch in line because I didn't think the TRS module would do the trick. So now I just leave the switch 'on' all the time.

 

What if you put high beams on? Did you put a diode?

 

Like if I flash my high beams?

 

^. I should've been more clear. Power from high beam instead of flashing your high beams