I am attempting to use the -12 pulse from my remote start to turn on an aux heater in my vehicle.

The remote start that will send out -12v for _about_ 1 second. I need to trip a circuit that will then produce a constant +12v.

Ideally I would like to be able to send the -12v pulse to unlatch the circuit and turn off the heater as required.

The draw on the circuit is minimal to the heater as it is only used as a signal.

Any help would be appreciated.

Mike

 

Is it realy -12V, or is just inverted 12V, i.e. sits at 12V, and then when you press the button, the signal goes to near ground, and then back to +12V?

 

I believe he did mean exactly what you said, I have not seen any remote starts that generate a negative voltage, only a LOW output..... it stays at 12 and pulses low for 1 second, (standard negative output on auto alarms and remote starts....)

 

I can explain further. The remote start's "trunk opening" output has no voltage and is not connected to ground. When I press the remote to activate the trunk the wire is grounded and would complete a 12v circuit.

Does that make more sense?

 

I can explain further. The remote start's "trunk opening" output has no voltage and is not connected to ground. When I press the remote to activate the trunk the wire is grounded and would complete a 12v circuit.

Does that make more sense?

It does indeed make more sense.

I hope that you understand that your battery will take a 'life hit" if you do what you propose.

 

Sorry, I don't understand, Life hit?

How would using the momentarily closed ground circuit from the remote start, to latch a relay that would supply +12 batter power to a heater circuit, affect the life of the battery?

 

Alternatively to being able to switch the circuit off by I could run it on a timer that would unpower the circuit after 60-90 minutes.

 

Sorry, I don't understand, Life hit?

How would using the momentarily closed ground circuit from the remote start, to latch a relay that would supply +12 batter power to a heater circuit, affect the life of the battery?

If your vehicle's engine is running when the heater is turned on, then it won't affect battery life. If the engine is not running, the battery will become discharged rather quickly. Heaters tend to draw a good bit of power. Automotive batteries don't survive very long if they are subjected to deep discharges.

 

Okay, I see where you are going. The heater is actually diesel fired
http://espar.com/html/applications/automotive.html
The circuit I require is only to power the control for the heater.