How to connect 9Vdc GPS to Arduino Uno 5Vdc

I just got my first Arduino board so I am new at this.

I have a Garmin 15xH-W OEM GPS receiver requiring 8Vdc to 40Vdc unregulated which I want to connect to Arduino Uno. I want to use 3 wires from the GPS, Red for Volts, Black for Gnd and Gray for the one second pulse. Uno only gives me 5V, so if I connect the Garmin to a 12Vdc supply, how do I connect Gnd to common for the GPS and the Uno?

With the power solved? how do I capture the pulse per second? Set a digital pin to output and read in a loop? I was not able to try this since I do not have a pulse yet.

The purpose is to count the 1 second pulses and then once every minute execute a new routine which will energize a relay and some more code after that. The relay requires 12Vdc to energize, so the same Common Gnd problem?

Your help will be appreciated very much.

if you read datasheet carefully electrical charactristic

you can give 3.3v to 5v as lower voltage.

if you want toi give 9v use 7809 regulator IC . output both can use to turn on GPS & controller(Vin pin)

Thanks AMPS-N

You put me on the right track. I now see that I can power the GPS from the Vin and Gnd pins. I tried it and it works, I get the 1 second pulse which I need :)

Now to get the program to work.

Thanks again.