illuminated pushbutton ignition

I want to wire in a pushbutton for my ignition. The button I am going to use is illuminated for use in the dark so how do I get the light to go out/switch off when the car has started? I don't really want to wire it into the handbrake to switch out the light when the handbrake's off, I'd rather it went out when the engine's fired up. I've tried to find the circuit for the dash lights that go out once the engine's started without any luck. Any ideas??

Don't use illuminated push button. Buy a 12v LED and a push button separately. Use a relay to start and turn off the LED.

Does your switch have a seperate positive lead that supplies the internal bulb or does the light illuminate via internal wiring?

the button has seperate leads to provide power to the internal led, if you put them across the battery the led lights up

thanks for that - much appreciated. How would I wire in the push start side?

just thinking about it - could I use the same configuration to switch on my dome light on alarm unlock and have it turn out when I started the car?? just wondering ..............

could I not use the alarm unlock neg pulse? or would I need a constant feed rather than a pulse?

You would need a constant feed