looking for relay circuit for hazards

Hi I am trying to figure out a circit which will activate when the hazards are active I can get a trigger on a relay to turn on another light.

Anyhelp woudl be great thanks.

Will

Unless your hazard switch activates a relay, you'd need a relay "AND" circuit - ie, if BOTH left & right are flashing - combined with a delay or "hold on" circuit - eg, Pulsed to Steady Output (Turn signal output to steady output for duration of turn signal).


Given the issues with that Pulsed to Steady Output circuit (eg, see pulsed to steady output resistor), I'd be tempted to use electronic sensing to activate the relay (else a transistor etc depending on what lights).

some vehicle info might be helpful

Hey the vehicle is an MB Sprinter but I am using a trailer module to isolate this from the SAM module.

Got it thanks.

the light bar I was trying to make this circuit for already has the logic I needed so I made two pulse to steady relays and I'm all good.

thanks

Another way of doing it would just be to grab the switched 12v (or ground however it's designed) before it goes to the flasher module. Sure would be simpler than using the pulsed to steady output converters.

That's what I meant by a "switched relay" or switched power that activates the hazards.   

But traditionally hazards don't work that way - they merely join the left & right sides as well as bypass the IGN +12V power - ie, the bulb switching is after the flasher can.
However, it might be possible to rewire the switched hazard +12V to actuates a DPST relay that then connects the hazard power to the can and powers the added light. An SPST relay could be used, by that requires a diode with a minimum 10A rating (if flashing 4x21W bulbs etc) which also means a 0.6V - 1V voltage drop to the can.

Great suggestions.
but I am trying to avoid touching the factory wire.
Also on the sprinter the hazards is controlled by the canbus

If it's canbus it is effectively a relay controlled hazard. Or that's my assumption - I'm relatively canbus ignorant - but it's a signalling protocol with everything "logic" controlled, ie the smarts control a relay type circuit (it might be solid state) to power the flasher-can or at least join the two sides... Unless they have progressed to the stage where everything (ie, bulb sockets) are canbus smart and do their own lamp control (but I doubt that - modern vehicle electronics still lag mine by at least 20 years).

IMO chances are that somewhere there will be a DC voltage to turn on the hazard circuit - probably even the hazard switch.
The hazard switch itself would probably be the easiest to tap into. But would that signify "touching" the factory wiring in your opinion?

Is there a wiring diagram else alternate detail that shows the hazard switch wiring? (Not that I like deciphering those VAG/German wiring diagrams!)


Oh rats - you have already solved the problem - my bad!
But too late, I've already hit the Post Reply button. (LOL - I figured I'd post this for next time.)