Pinpoint Test I: No Operation In Some Blower Speeds
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
- I1 CHECK THE BLOWER MOTOR SPEEDS
- Key in ON position.
- Turn the function selector switch to any position except OFF.
- Cycle the blower motor switch from high to low several times.
- Does the blower motor operate at all speeds?
Yes: If the blower motor operates correctly each time, ADVISE the owner of system operation.
If the blower motor does not operate correctly each time, INSTALL a new blower motor switch. REFER to REMOVAL AND INSTALLATION . TEST the system for normal operation.
No: GO to I2.
- I2 CHECK CIRCUIT 754 (LG/WH) FOR AN OPEN
- Key in OFF position.
- Disconnect: Blower Motor Resistor C293.
- Disconnect: Blower Motor Switch C294b.
- Measure the resistance between blower motor resistor C293-3, circuit 754 (LG/WH), harness side and blower motor switch C294b-c, circuit 754 (LG/WH), harness side.
- Is the resistance less than 5 ohms?
Yes: GO to I3.
No: REPAIR the circuit. TEST the system for normal operation.
- I3 CHECK CIRCUIT 752 (YE/RD) FOR AN OPEN
- Measure the resistance between blower motor resistor C293-2, circuit 752 (YE/RD), harness side and blower motor switch C294b-d, circuit 752 (YE/RD), harness side.
- Is the resistance less than 5 ohms?
Yes: GO to I4.
No: REPAIR the circuit. TEST the system for normal operation.
- I4 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Measure the resistance between blower motor resistor C293-1, circuit 57 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes: GO to I5.
No: REPAIR the circuit. TEST the system for normal operation.
- I5 CHECK THE BLOWER MOTOR SWITCH
- Key in OFF position.
- Measure the resistance of the blower motor switch, component side. Refer to the table shown in BLOWER MOTOR SWITCH TEST REFERENCE TABLE .BLOWER MOTOR SWITCH TEST REFERENCE TABLE
Switch Position Terminals Low None M1 A and C only M2 A and D only High A and B only - Is the blower motor switch OK?
Yes: INSTALL a new blower motor resistor. TEST the system for normal operation.
No: INSTALL a new blower motor switch. REFER to REMOVAL AND INSTALLATION . TEST the system for normal operation.