[pairodice]

I re-validated that:
1) with my multimeter on AC: If I connect the Black © wire and Yellow/black (W1) wire (Face of Ecobee pulled off): 27v AC
2) with my multimeter on AC: If I connect the Yellow/black wire to W1 wire with TStat OFF: ~4v AC
3) with my multimeter on AC: If I connect the Yellow/black wire to W1 wire and connected ground to the black © wire and the TStat ON I do get ~28v AC
2) I tested the yellow/black wire in the AH bay with my multimeter set to DC and the TStat ON; the wire going to the AH showed ~4v AC… not sure why the wire is not getting the full 28v to the transformer…
Question: when testing the yellow/black wire from the TStat (in the AH bay) I am connecting the ground on my meter to the a screw in the side of the AH unit - should this work for AC?
I can create a quick video of what I’m seeing if that helps… hopefully I typed in everything correctly.
I will try to run a wire out the window to get a good 24-volt ground from inside the coach at the TStat…