Momentary switch to active a relay?

I apologize in advance if this was asked before but I searched and could not find anything.

I'm trying to create a circuit that will kill the fuel pump and basically would automatically enable once the car was shut off. Pretty much I would like to have a momentary switch which would be power by the switched 12v in the car and a relay that it would drive. Simply speaking I would get into the car, put the key in and put it in the "RUN" position, hit this switch once and it would active a relay which would enable the fuel pump. Then the car could be started, once the car would be shut off, the power would no longer be supplied to the relay and it would open up again, therefore turning off the fuel pump. The problem I'm running into is I cannot figure out a way to keep the relay closed (proper term?) using a momentary switch.

basically the question is how can I keep the relay closed just by using a momentary switch or perhaps pulsing it? It's actually a 2 piece problem as it's supposed to turn off again once the car is turned off.

I guess i'm thinking more along the lines of a rear window defroster switch, usually it works as follows:

Press it once, it turns on the defroster, which stays on until it overheats or you manually turn it off. But once you shut off your car it automatically turns off anways, no matter what.

Thanks.

Basic Starter  Kill will do the same thing ...WithOUT the need for a extra Switch.  Can be done everytime you turn on Ignition Key....would activate Relay for Fuel Pump.  Turn Ignition OFF and Relay shuts Fule Pump  to "OFF"

If you HAVE to have extra switch....Use a LATCHING Relay