Pinpoint Test H: No Operation In Lower 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.

H1 CHECK THE BLOWER MOTOR SPEED
- 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 H2.
H2 CHECK CIRCUIT 261 (OG/BK) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: Blower Motor C2066.
- Disconnect: Blower Motor Resistor C293.
- Turn the blower motor switch to the low position.
- Measure the resistance between blower motor C2066-2, circuit 261 (OG/BK), harness side and ground.
  
  Fig 1: Checking Circuit 261 (OG/BK) For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes: INSTALL a new blower motor resistor. TEST the system for normal operation.

No: GO to H3.
H3 CHECK THE BLOWER MOTOR SWITCH FOR AN INTERNAL SHORT
- Disconnect: Blower Motor Switch C294b.
- Measure the resistance between blower motor switch C294b-a, circuit 261 (OG/BK), harness side and ground.
  
  Fig 2: Checking Blower Motor Switch For Internal Short
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes: INSTALL a new blower motor switch. REFER to REMOVAL AND INSTALLATION . TEST the system for normal operation.

No: REPAIR the circuit. TEST the system for normal operation.