On an E body with rear defrost.

How is the the rear blower wired from the dash mounted switch ?
Which side does said wiring run down the car ?

I have the switch and the rear blower housing and fan assy.

In my service manual there is nothing to go on.

Also, I've seen some rear defrosters with a resistor mounted on the hsg. But the assembly I have there is no resistor
,, should there be ?