2011 XTR Multispace heater blower switch?

[Chris Bryant]

Hi, I realize this is a common topic but I'm having real trouble trying to trace the problem with my heater/blower - the actual motor is the Denso one. I have replaced a blown relay and also replaced the resistor which was probably fine. I've bench tested the motor and it works. I only seem to be getting about 5 volts to the motor and I don't think that is enough to make it work. I just had a prod around at the back of the heater blower controls on the dash and looking at the big ampage wires in the middle (black, orange, white and yellow/green - I think)  I get 14V (full battery charge - engine running) when the switch is at OFF but as soon as I turn the switch to on I get nothing on the multimeter. Does anyone know how this unit is supposed to work? I don't know if I could still have a faulty relay or if the switch is just bust.
Does anyone have any advice or experience of testing the switch?