RE: volt meter
The ESV is generally connected through the charging jack of the switch harness. That gives it a line to the battery that sits in front of the switch, so the switch should be off. A loaded ESV is providing its own load, so there's no need or desire (it'd increase the load) to test in a way that leaves the electronics on. There's no need to have the RX on. You wouldn't need your TX on either.