[Bill Harris]

I think you are going to have to get your hands on the Ford Service manual that includes the electrical wiring diagrams in order to answer your question. The diagram will show whether the switches you refer to are directly switching the power to the device, or whether they are just control signals to a processor or control module. In this day and age, I would think that most switches are control signals as opposed to directly powering the device. It is much less expensive to build a switch that handles milliamps than amps, and the associated wiring can be a light gauge instead of big and heavy. Also, the car manufacturers like to be able to collect data on the settings of all the items in the car for "black box" information too, so having a module control the high current devices makes that easier too.

I could be totally wrong too, but it seems like a low current control setup would be significantly cheaper and lighter than the alternative, and it is cost that determines how something is done in a car design (unless the government says differently, of course).