Pinpoint Test P: The Blower Motor Does Not Operate Correctly - EMTC
Climate Control System
Pinpoint Tests
Pinpoint Test P: The Blower Motor Does Not Operate Correctly - EMTC
Refer to Wiring Diagram Set 54 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Manual Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the blower motor is provided a ground from the blower resistor. The resistor gets a ground through the entire resistor in the lowest blower setting. In MED-LO and MED-HI, the resistor gets a ground from the blower motor switch. In HI, the blower motor is grounded directly through the blower motor switch. The blower switch is grounded.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blower motor resistor
- Blower motor switch
PINPOINT TEST P: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - EMTC
-------------------------------------------------
P1 CHECK THE BLOWER MOTOR OPERATION
- Ignition ON.
- Turn the function selector switch to the FLOOR position.
- Select all blower speed positions.
- Does the blower motor operate in any position?
Yes
If the blower motor does not operate in HI setting only, GO to P2.
If the blower motor does not operate in LO setting only, GO to P3.
If the blower motor does not operate in MED-LO or MED-HI setting only, GO to P4.
If the blower motor operates in HI setting only, GO to P6.
If the blower motor operates in LO setting only, GO to P7.
For all other symptoms, GO to P8.
No
Go To Pinpoint Test O. Pinpoint Test O: The Blower Motor Is Inoperative - EMTC
-------------------------------------------------
P2 CHECK CIRCUIT CH430 (VT/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C2357B.
- Disconnect: Blower Motor C2004.
- Measure the resistance between blower motor switch C2357B-2, circuit CH430 (VT/OG), harness side and blower motor C2004-1, circuit CH430 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR circuit CH430 (VT/OG) for an open. TEST the system for normal operation.
-------------------------------------------------
P3 CHECK BLOWER MOTOR RESISTOR GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Resistor C293.
- Measure the resistance between blower motor resistor C293-4, circuit GD112 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor resistor. TEST the system for normal operation.
No
REPAIR circuit GD112 (BK/GN) for an open. TEST the system for normal operation.
-------------------------------------------------
P4 CHECK THE BLOWER MOTOR SWITCH
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
- Ignition OFF.
- Disconnect: Blower Motor Resistor C293.
For MED-LO inoperative
- For MED-LO inoperative: With the blower motor switch in the MED-LO speed position, connect a 12-volt test light between blower motor resistor C293-2, circuit CH430 (VT/OG), harness side and blower motor resistor C293-1, circuit CH428 (GN/WH), harness side.
For MED-HI inoperative
- For MED-HI inoperative: With the blower motor switch in the MED-HI speed position, connect a 12-volt test light between blower motor resistor C293-2, circuit CH430 (VT/OG), harness side and blower motor resistor C293-3, circuit CH429 (GY/BN), harness side.
- Does the test light illuminate?
Yes
INSTALL a new blower motor resistor. TEST the system for normal operation.
No
GO to P5.
-------------------------------------------------
P5 CHECK CIRCUIT CH428 (GN/WH) OR CH429 (GY/BN) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C2357B.
- Disconnect: Blower Motor Resistor C293.
For MED-LO inoperative
- For MED-LO inoperative, measure the resistance between blower motor switch C2357B-4, circuit CH428 (GN/WH), harness side and blower motor resistor C293-1, circuit CH428 (GN/WH), harness side.
For MED-HI inoperative
- For MED-HI inoperative, measure the resistance between blower motor switch C2357B-3, circuit CH429 (GY/BN), harness side and blower motor resistor C293-3, circuit CH429 (GY/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the Blower Motor Resistor component test. If the resistor tests OK, INSTALL a new blower motor switch. TEST the system for normal operation. Blower Motor Resistor
No
REPAIR circuit CH428 (GN/WH) or CH429 (GY/BN) for an open. TEST the system for normal operation.
-------------------------------------------------
P6 CHECK CIRCUIT CH430 (VT/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Resistor C293.
- Connect: Blower Motor C2004.
- Measure the resistance between blower motor C2004-1, circuit CH430 (VT/OG), harness side and blower motor resistor C293-2, circuit CH430 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor resistor. TEST the system for normal operation.
No
REPAIR circuit CH430 (VT/OG) for an open. TEST the system for normal operation.
-------------------------------------------------
P7 CHECK THE BLOWER MOTOR SWITCH GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C2357B.
- Measure the resistance between blower motor switch C2357B-1, circuit GD112 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR circuit GD112 (BK/GN) for an open. TEST the system for normal operation.
-------------------------------------------------
P8 CHECK CIRCUITS CH430 (VT/OG), CH428 (GN/WH) AND CH429 (GY/BN) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Blower Motor C2004.
- Disconnect: Blower Motor Resistor C293.
- Disconnect: Blower Motor Switch C2357B.
- Place the blower switch in the lowest setting.
- Measure the resistance between ground and blower motor resistor:
- C293-1, circuit CH428 (GN/WH), harness side.
- C293-2, circuit CH430 (VT/OG), harness side.
- C293-3, circuit CH429 (GY/BN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to P9.
No
REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
-------------------------------------------------
P9 CHECK THE BLOWER MOTOR CIRCUITS FOR SHORTS TOGETHER
- Measure the resistance between blower motor resistor:
- C293-1, circuit CH428 (GN/WH), harness side and C293-2, circuit CH430 (VT/OG), harness side.
- C293-1, circuit CH428 (GN/WH), harness side and C293-3, circuit CH429 (GY/BN), harness side.
- C293-2, circuit CH430 (VT/OG), harness side and C293-3, circuit CH429 (GY/BN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR the affected circuits. TEST the system for normal operation.
-------------------------------------------------