Combining 2 +12v wires in the car

[john2k]

I need to power an LED in the car from two power sources. One is from the IGN which activates when ignition is on and another is from a puddle light source which activates when you are near the car. Only problem is the puddle light stays on for a few seconds even after the ignition is turned on. So what I am thinking to do is add two 1n5822 signal diodes so that each circuit cannot provide power to the other circuit. Will this be sufficient or is there any other way?

 

[Bluejets]

Normally but it depends on how you connect everything. A diagram will help decide.

 

[duke37]

LEDs are cheap, use a separate one for each circuit.

 

[pepi]

Why does one need an LED to tell them the ING. is on?

There are plenty of visual indicators by default?