Pinpoint Test U: The Panel/Floor Control Is Inoperative Using The Front Auxiliary Climate Controls

WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

Test Step

U1 CHECK THE FLOOR MODE OUTPUT
- Disconnect: Air Distribution Door Actuator C3020.
- Key in ON position.
- Place the front auxiliary blower motor switch in HI and set the front auxiliary climate control assembly to FLOOR.
- Measure the voltage between the air distribution door actuator C3020-8, circuit 1128 (GY/LB) and C3020-7, circuit 1129 (BN/WH).
  
  Fig 1: Checking Floor Mode Output
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes

GO to U2.

No

GO to U3.
U2 CHECK THE PANEL MODE OUTPUT
- Set the front auxiliary climate control assembly to PANEL.
- Measure the voltage between the air distribution door actuator C3020-7, circuit 1129 (BN/WH) and C3020-8, circuit 1128 (GY/LB).
  
  Fig 2: Checking Panel Mode Output
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes

Check for a broken/binding auxiliary mode door. If OK, INSTALL a new air distribution door actuator. REFER to BLEND DOOR ACTUATOR - AUXILIARY . TEST the system for normal operation.

No

GO to U3.
U3 CHECK THE AIR DISTRIBUTION DOOR CIRCUITS FOR AN OPEN
- Key in OFF position.
- Disconnect: Front Auxiliary Climate Control Assembly C938a.
- Measure the resistance between the front auxiliary climate control assembly C938a-2, circuit 1128 (GY/LB) and the air distribution door actuator C3020-7, circuit 1128 (GY/LB), and between the front auxiliary climate control assembly C938a-4, circuit 1129 (BN/WH) and the air distribution door actuator C3020-8, circuit 1129 (BN/WH).
  
  Fig 3: Checking Air Distribution Door Circuits For Open
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes

GO to U4.

No

REPAIR the affected circuit. TEST the system for normal operation.
U4 CHECK CIRCUIT 1128 (GY/LB) AND CIRCUIT 1129 (BN/WH) FOR A SHORT TO GROUND
- Measure the resistance between ground and the front auxiliary climate control assembly:
  - C938a-2, circuit 1128 (GY/LB).
  - C938a-4, circuit 1129 (BN/WH).
  Fig 4: Checking Circuit 1128 (GY/LB) And Circuit 1129 (BN/WH) For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes

GO to U5.

No

REPAIR the affected circuit. TEST the system for normal operation.
U5 CHECK CIRCUIT 1128 (GY/LB) AND CIRCUIT 1129 (BN/WH) FOR A SHORT TO VOLTAGE
- Key in ON position.
- Measure the voltage between ground and the front auxiliary climate control assembly:
  - C938a-2, circuit 1128 (GY/LB).
  - C938a-4, circuit 1129 (BN/WH).
  Fig 5: Checking Circuit 1128 (GY/LB) And Circuit 1129 (BN/WH) For Short To Voltage
  Courtesy of FORD MOTOR CO.
- Is voltage present?
Yes

REPAIR the affected circuit. TEST the system for normal operation.

No

GO to U6.
U6 CHECK CIRCUIT 1129 (BN/WH) FOR A SHORT TO CIRCUIT 1128 (GY/LB)
- Key in OFF position.
- Measure the resistance between the front auxiliary climate control assembly C3020-8, circuit 1129 (BN/WH) and C3020-7, circuit 1128 (GY/LB).
  
  Fig 6: Checking Circuit 1129 (BN/WH) For Short To Circuit 1128 (GY/LB)
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes

INSTALL a new front auxiliary climate control assembly. REFER to AUXILIARY CLIMATE CONTROL ASSEMBLY - FRONT . TEST the system for normal operation.

No

REPAIR the affected circuit. TEST the system for normal operation.