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Home >> Mercury >> 2008 >> Milan Base, 3.0 1, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1681 (HVAC - Climate Control System - General Information And Diagnostics) >> Diagnostic Tests >> Climate Control System >> Pinpoint Tests >> Pinpoint Test F: DTC B1259 or B1261 >> Pinpoint Test F: DTC B1259 Or B1261

Pinpoint Test F: DTC B1259 Or B1261

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
  1. F1 CHECK THE HVAC MODULE OUTPUT VOLTAGE 
    • Key in OFF position.
    • Disconnect: Solar Radiation Sensor C287
    • Key in ON position.
    • Press the AUTOMATIC button.
      • Fig 1: Measuring Voltage
      GF0018836Courtesy of FORD MOTOR CO.
    • Measure the voltage between solar radiation sensor C287-1, circuit 468 (BN), harness side and C287-2, circuit 676 (PK/OG), harness side.
      • Fig 2: Measuring Voltage
      GF0004297Courtesy of FORD MOTOR CO.
    • Measure the voltage between solar radiation sensor C287-2, circuit 676 (PK/OG), harness side and C287-6, circuit 476 (BN/YE), harness side.
    • Are the voltages between 4.7 and 5.1 volts? 
    1. YES  : INSTALL a new solar radiation sensor. CLEAR the DTCs. REPEAT the self-test. If the DTC returns, go to  F6.
    2. NO  : If diagnosing DTC B1259  , go to  F2.

      If diagnosing DTC B1261  , go to  F4.

  2. F2 CHECK CIRCUITS 468 (BN) AND 476 (BN/YE) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: HVAC Module C228b
      • Fig 3: Measuring Resistance
      GF0047631Courtesy of FORD MOTOR CO.
    • Measure the resistance between HVAC module C228b-6, circuit 468 (BN), harness side and solar radiation sensor C287-1, circuit 468 (BN), harness side.
      • Fig 4: Measuring Resistance
      GF0047632Courtesy of FORD MOTOR CO.
    • Measure the resistance between HVAC module C228b-18, circuit 476 (BN/YE), harness side and solar radiation sensor C287-6, circuit 476 (BN/YE), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  F3.
    2. NO  : REPAIR the circuit for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
  3. F3 CHECK CIRCUIT 676 (PK/OG) FOR AN OPEN 
      Fig 5: Measuring Resistance
      GF0004298Courtesy of FORD MOTOR CO.
    • Measure the resistance between solar radiation sensor C287-2, circuit 676 (PK/OG), harness side and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  F6.
    2. NO  : REPAIR circuit 676 (PK/OG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
  4. F4 CHECK CIRCUITS 468 (BN) AND 476 (BN/YE) FOR A SHORT TO CIRCUIT 676 (PK/OG) 
    • Key in OFF position.
    • Disconnect: HVAC Module C228b
      • Fig 6: Measuring Resistance
      GF0018839Courtesy of FORD MOTOR CO.
    • Measure the resistance between solar radiation sensor C287-1, circuit 468 (BN), harness side and C287-2, circuit 676 (PK/OG), harness side.
      • Fig 7: Measuring Resistance
      GF0018840Courtesy of FORD MOTOR CO.
    • Measure the resistance between solar radiation sensor C287-6, circuit 476 (BN/YE), harness side and C287-2, circuit 676 (PK/OG), harness side.
    • Are the resistances greater than 10,000 ohms? 
    1. YES  : Go to  F5.
    2. NO  : REPAIR circuit 468 (BN) or 476 (BN/YE) for a short to circuit 676 (PK/OG). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
  5. F5 CHECK CIRCUITS 468 (BN) AND 476 (BN/YE) FOR A SHORT TO GROUND 
      Fig 8: Measuring Resistance
      GF0018841Courtesy of FORD MOTOR CO.
    • Measure the resistance between solar radiation sensor C287-1, circuit 468 (BN), harness side and ground.
      • Fig 9: Measuring Resistance
      GF0004301Courtesy of FORD MOTOR CO.
    • Measure the resistance between solar radiation sensor C287-6, circuit 476 (BN/YE), harness side and ground.
    • Are the resistances greater than 10,000 ohms? 
    1. YES  : Go to  F6.
    2. NO  : REPAIR circuit 468 (BN) or 476 (BN/YE) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
  6. F6 CHECK HVAC MODULE CONNECTION 
    1. YES  : INSTALL a new HVAC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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