Wiring circuit to be on O N L Y when the car is OFF

[SD_GR]

I've done this once but can't for the life of me remember how I did it.

I want a circuit to be ON but only when the car itself is OFF.

How?

[GarrettKoonsman]

well i cant help you but this is an interesting question... What on earth could you possibly be doing?

[Sinister]

well i cant help you but this is an interesting question... What on earth could you possibly be doing?

my curiosity is peaked

[Graham46]

Me too since this is coming from Mr. Stock himself

[Scuba2708]

um...maybe a relay that is open when the key is in the on position and closed when ignition is off, run the other part to a constant power and there you go. if i suck at explaining im sorry i could try a more detailed answer.

any hint on what its for?

[SD_GR]

um...maybe a relay that is open when the key is in the on position and closed when ignition is off, run the other part to a constant power and there you go. if i suck at explaining im sorry i could try a more detailed answer.

any hint on what its for?

This sounds very familiar, yes... This is probably along the lines of what I did.

Imagine you are wiring a parking lamp -- a true parking lamp! Something low current, 12V, and on only when the car is parked, and you are out of the car with the key (all night, for example).

OK, so... to wire it conventionally and have the lamp on with the key on, it's 87 to the lamp, 85 to ground, 86 to the ignition (the key) and 30 to positive power (battery). To wire it how I want, what do I re-arrange? 85 and 86? Do I wire 85 to the key and 86 to ignition? I'm still confused...

[GarrettKoonsman]

I would think you would have to put an "override" switch somewhere. Otherwise you leave for a week and come back to a dead battery

[mangostick]

I've done this once but can't for the life of me remember how I did it.

I want a circuit to be ON but only when the car itself is OFF.

How?

build a latch.. see here

http://www.the12volt.com/relays/page5.asp#drto

instead of a door opening to kill the circuit, could just set it up on a toggle switch. This way, when you want to disable the circuit you can but ordinarily it will stay powered when you shut the car off. You could also wire in a relay to trip the circuit into the off mode when you turn the key to start the car. That way off when car on.. on when car off. Relays are you're friends.

www.the12volt.com massive amounts of info, tips n tricks.

[SD_GR]

Thanks, I looked at that site while googling for an answer... but maybe I'm being dense because I see how to set up the latch so that power is cut off when a door opens, but I don't want that. What I want is power to remain on until the key is turned to on, at which point I want power off. I'm going to stare at the diagramme a bit more because I am probably missing something simple and crucial at this point. Thanks again!

[fahr_side]

OK, so... to wire it conventionally and have the lamp on with the key on, it's 87 to the lamp, 85 to ground, 86 to the ignition (the key) and 30 to positive power (battery). To wire it how I want, what do I re-arrange? 85 and 86? Do I wire 85 to the key and 86 to ignition? I'm still confused...

First off, you have that a little backward. 87 should be B+ and 30 should be +ve to the load.

To wire it as 'normally off', run B+ to 87A. Wire 86 to either ignition or acc +ve as you like. 85 to ground. 30 will be hot when 86 isn't.

BCAE is also a lifesaver when your brain gets stuck.

[Heide264]

Are you still looking into this? If you could post some more details as to when you want this circuit to actually be off it would help.

Ex. Off while car is on, On while the car is off and key is in, Off when car is off and key is out.

You have a couple options either way.

[SD_GR]

OK thanks everyone.

This is where I'm heading: I want the circuit OFF when the car is on, and ON when the car is off and the key is removed.

[mudferret]

Here's my useless think tank input: I immediately thought of the park switch in a wiper motor. Wondering if a similar scheme to accomplish what you're after. As far as adapting it for your needs I'll begin my 18 month study.....now.

[MainFrame]

So basically you just need a relay that is open when ACC power is on and closed when ACC power is off?


According to this site all you would have to do is hook up your parking lights to pins 30 and 87a (instead of 87). Then have your ACC power going to 85 and ground 86 (or vice-versa).


I think that would do it.

[Heide264]

So basically you just need a relay that is open when ACC power is on and closed when ACC power is off?


According to this site all you would have to do is hook up your parking lights to pins 30 and 87a (instead of 87). Then have your ACC power going to 85 and ground 86 (or vice-versa).


I think that would do it.

I agree. However, this seems rather strange. I'd at least use a timer or something on it to make sure it doesn't run for a week straight.