[Richard]

The tstat wires go directly to the AH.

Look at your first picture. Look at the labels and wire colors on the top of the terminal strip.

Now look to the immediate left of the terminal strip and you will see the relay to convert 12 Pos to ground. The wire from the tstat is going to the cube relay.

Forget the wire tracer. There is a reason I suggested you do the following items.

Check the back of the tstat to ensure that it is putting out 24V. I think it may now be 24V AC not DC with the conversion you did.

Now to the AH and look at those wire colors and use the voltmeter to confirm voltage. Remember you are looking for voltage going into the cube relay. If you measure at the terminal strip you will get NADA, because AH is looking for a ground on those terminals to activated the zone.

I think you are going to have to replace the cube relays with ones that have a coil compatible with the voltage and AC ? DC? That your tstat is outputting.

Just for giggles, take a jumper wire from a ground source and touch it to one of three terminals for the three zones. The pump should activate, and the kick fans inside should activate.