My best guess is that pin 1 is used to turn on the deck from a remote input. Pin 2 is used to tell the remote device that the deck is on.

There are a few conditions that must be met before you can try a test. The 47k resistor must be connected to the base of the transistor (the vertical line) and nowhere else. The emitter of the transistor (the arrow) must be grounded. I don't mean to sound condescending, I just don't know how much electronics you know.

If these conditions are true, no harm will be done by connecting pin 1 to 12V to see if the deck comes on. The key will have to be in the on or accessory position when you do the test.

Good Luck!