2000 Mercury Grand Marquis EATC Module

The blower motor isn't working in this.  It hasn't for about a year or so now.  Over 2 years ago, I replaced the blower motor and the blower motor speed controller (BMSC), and it worked just fine for several months.  The speed control module was the culprit at that time.  But now it's back to not working.  I'm afraid it's the Electronic Automatic Temperature Control (EATC) Module in the dash.  I can disconnect the BMSC connector and jump the 2 blower motor wires, and the motor runs at full blast, so I know the motor itself is OK.  I have some service tips that my mechanic printed out for me, and they say to monitor the voltage of the yellow/red wire in the BMSC connector as I move the blower speed thumb wheel.  Voltage is supposed to be between 1.0 and 3.0.  I'm getting over 11V. (It does read slightly lower voltage at high fan speed and slightly higher voltage at low speed - we're talking readings that range from 11.05V to 11.20V.)  So I suppose it's possibly a short in that wire between the BMSC connector and the EATC module, but I'm thinking it's more likely a failed component in the EATC.  Can you all fix that?