LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 174 (HVAC Control System - General Information -- F250-F550 Super Duty) >> Diagnosis And Testing >> Climate Control System >> Pinpoint Tests >> Pinpoint Test O: The Blower Motor Operates Continuously In High Speed - Manual Climate Control

Pinpoint Test O: The Blower Motor Operates Continuously In High Speed - Manual Climate Control

WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
  1. O1 CHECK THE FUNCTION SELECTOR SWITCH 
    • Key in ON position.
    • Set the blower motor speed to maximum.
    • Check for blower motor operation in each function selector switch position.
    • Does the blower motor operate in all of the function selector positions except OFF? 
    • Yes  : GO to O2.
    • No  : GO to  O3.
  2. O2 CHECK CIRCUIT 261 (OG/BK) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: Blower Motor C1031.
    • Disconnect: Blower Motor Resistor C1032.
    • Disconnect: Blower Motor Switch C294c.
    • Measure the resistance between blower motor connector C1031, circuit 261 (OG/BK) and ground.
      Fig 1: Checking Circuit 261 (OG/BK) For A Short To Ground
      G03910194Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 
    • Yes  : INSTALL a new blower motor switch. REFER to CONTROL COMPONENTS . TEST the system for normal operation.
    • No  : REPAIR circuit 261 (OG/BK) for a short to ground. TEST the system for normal operation.
  3. O3 CHECK CIRCUIT 399 (BN/YE) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: Function Selector Switch C294a.
    • Disconnect: Blower Motor Relay.
    • Measure the resistance between function selector switch connector C294a pin 3, circuit 399 (BN/YE) and ground.
      Fig 2: Checking Circuit 399 (BN/YE) For Short To Ground
      G03910195Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 
    • Yes  : INSTALL a new function selector switch. REFER to CONTROL COMPONENTS . TEST the system for normal operation.
    • No  : REPAIR circuit 399 (BN/YE) for a short to ground. TEST the system for normal operation.