switched negative trigger in a car???

[Andrew_as 10+ year member]

So my friend has a 1989 buick electra. I am going to put one of the fake led alarm scanning lights in it. The thing is, the wire to turn it on and off is a negative trigger wire. So i was wondering if anyone knows of a wire that would a switched negative.

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[Andrew_as 10+ year member]

no ideas?

 

[ShiningBuick 10+ year member]

**** near everything on cars is switched negatively.

When do you need it to turn on?

What I would do is this (attachment). It'll turn off when the car is on, and will provide a ground when the car is off.

 

[audioarsonal 10+ year member]

You need a SPDT relay.Wire 12v pos to poles 86 and 30 wire the switched circut to 87 and the device to be triggered to 85.

 

[Ferendon 10+ year member]

You need a SPDT relay.Wire 12v pos to poles 86 and 30 wire the switched circut to 87 and the device to be triggered to 85.

He needs negative trigger. You'd have ground to 85 and 87, ignition to 86, light bar on 30.