lack probe connected to (-) of meter.
Red probe connected to (+) of meter.
Disconnect anything going to the Lock wire on the alarm system.
Connect the red wire of the meter to some source of 12V.
Connect the black wire of the meter to Lock
Observe meter - You should have 0 Volts
it's 2 volts
Activate Lock - You should have "some voltage pulse" for a second or so.
Yes I got 12.08 v
The should have 12 V is ideal. You might actually have 12 V for this test in both conditions because of leakage currents, so nothing might happen.