All the screens are slightly different so look at the list below for the dual circuit screens, they have a live and earth wire on BOTH sides, most are in the bottom corners apart from on some Escorts it has one in the bottom corner and the other at the top.
Each side needs wiring through a fuse, relay and then a switch on the dash to trigger the two relays (you can use timer relays if you want but not essential).
Details below of estimated current draw for each screen you have ordered, we usually recommend 2 x 25 amp circuits BUT you will see below there can sometimes be some flex on this.
Impreza GC8 = 18amps each side
Legacy = 18amps each side
Starlet = 13 amps each side
AE86 = 14 amps each side
MK1 Escort = 12 amps each side
MK2 Escort = 12 amps each side
Cortina Mk1 = 10 amps each side
E30 = 16 amps each side
RX8 = 18 amps each side
Fabia = 19 amps each side
Mirage = 18 amps each side
Now as the screen heats up it will start to draw slightly more and when you turn it on it can spike, hence the 25 amps suggestion.
IMPORTANT – on rubber fit screens you must seal the glass inside the rubber with non setting black windscreen sealant, this protects the heated elements from water ingress. On bonded screens you can (if you wish and we would recommend) paint 3 coats of the primer you would use to fit the screen around the 5mm edge as this again protects the edges from water.