Little update here. The drivers seat works fine but not the passenger. Wire testing shows voltage at the supply wires so we are suspecting the pads. However, it would seem odd that both pads in one seat do not work? Also, should the voltage vary with operation of the switch? At the moment it is showing 13v (engine on) at all stages.
the 2 pads are connected in series, so a break on one pad will take them both out. use a multimeter to probe for continuity at the 2 pad connectors, usually its the seat base one though
Thanks John, that's very helpful. Should there be any variance in the voltage at the different switch levels?
I've not actually tested one, I assumed it was varying voltage but it could be pwm or something. is the thermistor in the pad working? that should see similar resistance to the other side