connector

while underneath my dash resetting the SRS system, I noticed a second green connector located beside the keyless entry module. there is nothing connected to it and i see nothing disconnected that should be connected to it. does anybody know what this connector is for?

I need to install a amateur radio and need 12 power but only when the ignition is on. As the radio draws heavy amp. We use what's called a 'A Relay'. When the ignition comes on, it will energize the relay which has big wire connection to the battery. When ignition is off, the relay drops out...