Brown power-in to heater blower switch
 

This is on my wifes Chevy Venture but I think the wiring is the same on many Chevys. This started out as a typical front heat blower not working, and jumping the gun I changed the blower resister to no avail. So I started some research. I found out that the brown power in wire from the fuse block (interior right side dash) has no power. This brown wire, is the power at the speed selector switch which then runs through the resistor, and even energizes the high power relay to run the blower on high. According to the wiring diagram this brown wire is "HOT IN RUN" which then goes through a 25 amp fuse. Interestingly, there are three fuses associated with the heat, a 10, two 25s, and a 30. The feed side of the two 25s (FRT HVAC LOW MED) has no power in. So my question is, where is the feed side of those fuses? I am thinking maybe the ignition switch? Because they shouldn't be energized unless the ignition is on. But I can't find that detail on any wiring diagram.