on the circuit board side (all the electrical componetry side) there will be/should be what looks like a square black component soldered on to the circuit board, this is the relay. The pins from this black square (relay) are what require the earth signal to trigger the lock/unlock.. very tentively use a test light to find what pins (should be 4 pins intotal at a guess) have 12v.. if no voltage on other pins, they are more than likely the lock/unlock, tentitively touch an earth on to them to see if the click and operate the doors.. if you are lucky your test light will do his when you probe them for power or not.
Failing that, take the box into a reputable car alarm installer and they will show you in 3 seconds flat
prolly look like this: