Ford Repair: blower motor speed control, ford explorer eddie bauer, motor speed control

Question
1996 Ford Explorer, Eddie Bauer.
First the blower motor wouldn't turn on so I replaced the resistor, then the motor would run but all I have is high, was told to replace the switch, well can't change just the switch had to change the whole control box because I have automatic temp control, this didn't help, what should I check next????
Thanks Bill  

Answer
I've enclosed the pinpoint tests from the workshop manual for your particular concern, all odds point to the a/c controller as it also can affect blower motor speed.  Write back if you have further questions.

Hope this helps
Sek

PINPOINT TEST C: EATC HEATER BLOWER MOTOR OPERATES IN HIGH IN ALL BLOWER WHEEL POSITIONS
 
C1 PERFORM EATC SYSTEM CHECK COMPONENT TEST
Perform the EATC System Check Component Test in this section.
Does the EATC system check OK?
Yes  No  
GO to C2 .  SERVICE as necessary. REFER to EATC System Check Component Test.  
 
C2 CHECK BLOWER MOTOR OPERATION
Start engine and select MAX A/C and position between HI and LO. The blower motor should operate at approximately medium speed.
Is blower motor speed reduced from high speed?
Yes  No  
REFER to EATC system function test.  GO to C3 .  
 
C3 CHECK VOLTAGE SIGNAL TO EATC ALL BLOWER SPEEDS
Disconnect the harness connector from the A/C blower motor speed control.
Engine running, select MAX A/C and set blower thumbwheel at LO.
Check for voltage between Pin 2 (Circuit 181 [B/O]) and Pin 5 (Circuit 57 [BK]) of the harness connector while rotating the blower motor thumbwheel. The voltage reading should be between 1 and 2 volts for all thumbwheel settings, 0 volts at HI.
Is voltage between 1 and 2 volts except in HI?
Yes  No  
GO to C5 .  If 0 volts, GO to C4 . If above 2 volts, REPLACE A/C control.  
 
C4 CHECK VOLTAGE SIGNAL TO EATC WITH MAX A/C
Reconnect harness connector to A/C blower motor speed control.
Engine running, select MAX A/C and set the blower thumbwheel for a medium speed.
Check the voltage at Pin 7 (Circuit 181 [B/O]) of the EATC control assembly.
Is the voltage between 1 and 2 volts?
Yes  No  
SERVICE Circuit 181 (B/O).  REPLACE A/C control.  
 
C5 CHECK VOLTAGE TO BLOWER MOTOR SPEED CONTROL
Check voltage between Pin 3 (Circuit 775 [W/PK]) and Pin 5 (Circuit 57 [B/K]) of blower motor speed control with the blower speed thumbwheel at any position except HI.
Is the voltage measurement zero?
Yes  No  
REPLACE A/C blower motor speed control.  REPLACE the A/C control.