otis 211 eru unit

anyone have a wiring diagram for the otis ERU battery lowering unit?
i have a few units that are not working, and the batteries are good. i can see most of the wiring points that go to the eru on the print, however i can't seem to find the wiring for how the ERU knows that the main line power is missing. I've been over that print for an hour now, and still can't see it. seems like it would be on the main print, but i can't find.

Sounds like a dumb reply but r there any Aux contacts from the hook to trace?

aux contacts are functioning properly rang them out all the way to the ERU wiring harness.

I had a similar problem, never got what I really wanted for info on that thing. I sent you what I have, it was enough to figure out what was wrong with mine but it's not much.

thanks indy , after looking at what you sent me i have a couple ideas, now i can at least see the terminals that would sense removal of ac power. also i noted that it said the unit will not turn on if the voltage is below 24-25 volts. not sure how this is working, as only have 2 12 volt batteries which equal 24 volts. but maybe the charging circuit and capacitors on the board boost it up to the recommended voltage of 27 volts to operate correctly. probably as simple as new batteries, even though i was reading 24 volts. will see thanks again.

If the voltage needle isn't between the two tick marks at fully charged it won't respond. Also check the parameters to make sure it is turned on and the has a designated floor to respond too.

What does it take to remove the eru