Normally a B.I.R.D., senses when the chassis batteries have reach a full charge and energizes a relay or solenoid, whatever you wish to call it. When the solenoid energizes, the house batteries receive power from the chassis alternator.
There should be two heavy wires attached to the contacts and one small wire to the coil of the solenoid..
Jumper from the hot side of the solenoid to the smaller wire,if the solenoid makes a loud click, it would appear to be working and using atest light or DMM connected to the load side of the slenoid should light up.
If you start the engine and allow it to run for a few minutes, the BIRD should send 12 volts through the small wire on the coil of the solinod. A test light connected to that small wire and ground should light up when the chassis battery is charged enough and the BIRD sends power through that wire.
If after starting the engine and letting in run for 10 or 15 minutes and the test light doesn't come on, it would seem you have a bad BIRD.
You should be able to search on line and find more concise testing instructions.
