If you reallllly want to know what 'it' is, you can do this:
- it is probably a simple two contact relay
- one set of wires for the relay coil, other set for the contacts
- measure the two brown wires & then the two black wires for resistance.
- if you get resistance [ likely to be 50-200 ohms ], those wires are the coil wires.
- if measure open cct on the other set of wires, should be the contacts
- apply 12v to the coil wires & you should measure zero or close to zero ohms on the remaining two wires. You may hear or feel the relay 'click'.