Originally Posted by CountryB
I think you are describing the same thing - both units are separate but have wires that connect to locks (grounds).
In the diagram it looks like the wires from Essex and KL550 go to each other and no where else - but they may be connected together at the point where they "connect to door lock motor ground wire".
If this is the way it works - then would the power door lock motor have +12V power all the time and only operate/open-lock when ground is applied?
I don't know for sure.
I'm not sure it's a super-important distinction, but I think mine is different.
The Remote Lock and Remote Unlock wires on my Essex keypad do go into the plug, but my wiring diagram doesn't show them going all the way to the wireless unit.
In the diagram you attached, which is also detailed in my old original Essex paperwork, the wireless module grounds the Essex keypad's "Remote Lock/Unlock" wires; which triggers the Essex keypad to ground the lock relay.
In my arrangement, I beleive the two units each directly ground the lock relay.
In other words, the wireless module doesn't connect to the Essex orange and white wires, it connects to the same relays that the Essex Lock and Unlock wires connect to.
The lock motors don't have power applied all the time; there are relays in the forward electrical bay that power the lock motors to lock and unlock.