Pinpoint Test P: The Auxiliary Blower Motor Is Inoperative: Testing

WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.

P1 CHECK CIRCUIT 536 (BK/LG) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Auxiliary Blower Motor C3021.
- Key in ON position.
- Measure the voltage between auxiliary blower motor C3021-1, circuit 536 (BK/LG) and ground.
  
  Fig 1: Checking For Voltage To Blower Motor
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to P6.
- No : GO to P2.
P2 CHECK CIRCUIT 181 (BN/OG) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Auxiliary Blower Motor Relay 1.
- Key in ON position.
- Measure the voltage between the auxiliary blower motor relay 1 socket pin 30, circuit 181 (BN/OG) and ground.
  
  Fig 2: Measuring Voltage Between Relay Socket And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to P3.
- No : REPAIR circuit 181 (BN/OG) for an open. TEST the system for normal operation.
P3 CHECK CIRCUIT 1004 (LB/RD) FOR VOLTAGE
- Measure the voltage between the auxiliary blower motor relay 1 socket pin 85, circuit 1004 (LB/RD) and ground.
  
  Fig 3: Measuring Voltage Between Relay Socket Terminal And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to P4.
- No : REPAIR circuit 1004 (LB/RD) for an open. TEST the system for normal operation.
P4 CHECK CIRCUIT 1371 (TN/OG) FOR GROUND
- Measure the resistance between the auxiliary blower motor relay 1 socket pin 86, circuit 1371 (TN/OG) and ground.
  
  Fig 4: Measuring Resistance Between Relay Socket And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : CARRY OUT the relay component test on the auxiliary blower motor relay 1. If OK, REPAIR circuit 536 (BK/LG) for an open. TEST the system for normal operation.
- No : GO to P5.
P5 CHECK CIRCUIT 1371 (TN/OG) FOR AN OPEN
- Key in OFF position.
- Disconnect: EATC Module C228a.
- Measure the resistance between EATC module C228a-23, circuit 1371 (TN/OG) and auxiliary blower motor relay socket pin 86, circuit 1371 (TN/OG).
  
  Fig 5: Measuring Resistance Between EATC Module C228A-23 And Auxiliary Blower Motor Relay Socket Pin 86
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a new EATC module. TEST the system for normal operation.
- No : REPAIR circuit 1371 (TN/OG) for an open. TEST the system for normal operation.
P6 CHECK CIRCUIT 515 (OG/RD) FOR GROUND
- Key in OFF position.
- Measure the resistance between auxiliary blower motor C3021-2, circuit 515 (OG/RD) and ground.
  
  Fig 6: Measuring Resistance Between A/C Blower Motor Connector And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a new auxiliary blower motor. TEST the system for normal operation.
- No : GO to P7.
P7 CHECK CIRCUIT 1205 (BK) FOR GROUND
- Key in OFF position.
- Disconnect: Auxiliary Blower Motor Resistor C3022.
- Measure the resistance between auxiliary blower motor resistor C3022-2, circuit 1205 (BK) and ground.
  
  Fig 7: Measuring Resistance Between Auxiliary Blower Motor Resistor C3022-2, Circuit 1205 (BK) And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : CARRY OUT the component test on the Auxiliary Blower Motor Resistor . If OK, REPAIR circuit 515 (OG/RD) for an open between the auxiliary blower motor and splice S396. TEST the system for normal operation.
- No : REPAIR circuit 1205 (BK) for an open. TEST the system for normal operation.