I found this in the RAVE electrical library manual for the heated mirrors (Pg 4.27 & 4.28)...
Mirror heater
The LH and RH door mirror heaters are connected from the heated rear screen relay in the
passenger compartment fusebox on an NP wire via splice joints A19/A167.
When the heated rear window switch is operated an earth path is completed from the switch
on a B wire, via header C0760, to earth header C0017 LHD/C0018 RHD. The switch is
connected on an NB wire to pin C0663-5 on the BCU.
On vehicles with Air Temperature Control (ATC), when the demist function is selected the
ATC ECU provides an earth path on an NB wire through splice joint A249, to pin C0663-5
on the BCU.
The completed earth path is interpreted by the BCU as a signal for heated rear screen
operation. The BCU is connected from pin C0661-1 on an SK wire to the the IDM in the
passenger compartment fusebox. The SK wire is the serial data bus between the BCU and
the IDM. The BCU passes a signal to the IDM which in turn provides an earth path, on a B
wire to earth header C0551, for the coil of the heated rear screen relay in the passenger
compartment fusebox.
The heated rear screen relay coil is energised by the feed from fuse 13 in the engine
compartment fusebox causing the relay contacts to close. With the contacts closed, a feed
from fuse 8 in the passenger compartment fusebox passes through the relay and is
connected from the fusebox on an NP wire to splice joints A19/A167. From the splice joints
the feed is connected on NP wires to the driver and passenger door mirror heaters.
On LHD vehicles, the driver’s door mirror heater is connected on a B wire, via splice joint
A34 and header C0288, to earth header C0017. The passenger door mirror heater is
connected on a B wire, via splice joint A34, to earth header C0018.
On RHD vehicles, the driver’s door mirror heater is connected on a B wire, via splice joint
A34, to earth header C0018. The passenger door mirror is connected on a B wire, via splice
joint A34, to earth header C0017.
The door mirror heaters will operate for as long as the heated rear screen relay is energised.