Owner's manual can be downloaded here:
http://www.qualitycareservice.com/default.asp?page=E4Interior fuse panel above driver's left foot. There's a button/lever you operate on inboard side which allows panel to flip down. Akward area to see and work in.
If fuse ok use your tester on wires(BK/R & P/BL) at motor connector ignition on (with your temp feed disconnectd) they should both show power (to ground) when connected to motor and only one(P/BL) should show power (to ground) when the connector is pulled off the motor. Visually check wiring/connector at blower resistors for similar symptoms to what you found at switch.
Short (ie power wire touching ground) more difficult to find than open circuit (discontinuity in either power or ground wire).