My Trane XT500C thermostat has bitten the dust, and I'm replacing it with a Honeywell VisionPRO 8000 (model #TH8320U1008), the model Trane said is the proper replacement for the XT500C. The current wiring to the XT500C is as follows:

B - Blue
H - {no connection}
H - {no connection}
OT - {no connection}
OT - {no connection}
F - {no connection}

R - Red
W - White
Y1 - Green
Y2 - Yellow
X2 - White
O - Red
G - Green

The thermostat is wired to a Trane air handler (TWE049E13FB0) w/a heat pump (BAYHTR1410). The wires are in two separate conduits, five wires in one (Red, White, Green, Yellow, & Blue), three in the other (Red, White, Green).

The Honeywell thermostat connection points are labeled:

Y2
L
E
AUX
S1
S2

RC
R (jumper between R&RC)
O/B
Y
G
C

I cannot find definitive direction on which wires from the Air Handler are performing which function so that I can make the proper connections to the new thermostat. Any help from someone who has made this change before would be greatly appreciated.

All the wires should go the same except the blue wire, that one should go in the " C " any question let me know

I figured the blue wire would connect at the C juncture, however, I'm still left with many unknowns:

There is no 'W' on the Honeywell for the heat pump side (it coincides with the O/W, which should receive the second red wire).

There's no 'X2' on the Honeywell

Y1 is currently hooked up to a green wire, while the yellow is connected to Y2, does the yellow remain on Y2 and the green now go to Y?

I'm almost there, but still far enough away to do some serious damage to the overall system if I get it wrong...