Are you saying this relay supports 4 accessories? if 1,3,2, and 4 are all positive?
Nothing is positive or negative in a circuit until you wire it that way.
Another drawing of a DPDT relay that's maybe a bit clearer:
Pay no attention to the colors on the drawing, only the terminal names. To power up your accessory, you need a B+ and a B- signal to the relay coil terminals to activate the relay. If you want to use your license plate light to activate the relay, then hook your lamp wires to the coil terminals of the relay. Before going any further, turn the keyswitch on and verify that the relay clicks when you turn it on.
Next, you'll need to attach B+ power to one of the "common" terminals, and power out to the accessory you're adding to one of the "normally open" terminals. "Normally open" and "normally closed" simply indicate that terminal's relationship to the "common" terminal directly above it. When the relay isn't powered up, (clicked "on" by your lamp circuit), then there's no connection made between the "common" and "normally open". There is a connection made between the "common" and "normally closed". Simple as that.
For your application, you won't be using
any of the "common", "normally open", and "normally closed" terminals on one side....so as already mentioned.....you have more relay than you need here. Get a simple relay like this:
and wire it up like this:
85 and 86 get power from your lamp circuit. 30 gets B+ power from your battery and sends it out to 87 when you turn the key on and the relay clicks on. 87a will have B+ power when the key is off....so don't use it. It won't drain your battery
unless you wire something to it
to drain your battery. If you wanted to, you could connect B+ power to the 87 terminal and attach your accessory to the 30 terminal....the relay won't care a bit. It simply connects the 30 and 87 together when it's told to by the lamp circuit.
Finally, don't make a mess of the wiring by crimping on a bunch of individual terminals....get a relay socket to match the relay you're using.
