Pinpoint Test H: No Communication With The Dual Automatic Temperature Control Module

Test Step 

H1 CHECK CIRCUIT 676 (PK/OG) FOR AN OPEN 

• Key in OFF position.
• Disconnect: DATC Module C228a.
• Measure the resistance between the DATC module C228a-2, circuit 676 (PK/OG) and ground.
  Fig 1: Checking Circuit 676 (PK/OG) For An Open

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms? 

Result / Action to Take 

Yes 

GO to H2.

No 

REPAIR circuit 676 (PK/OG) for an open. TEST the system for normal operation.

Test Step 

H2 CHECK CIRCUIT 729 (RD/WH) FOR B+ 

• Disconnect: DATC module C228b.
• Measure the voltage between the DATC module C228b-11, circuit 729 (RD/WH) and ground.
  Fig 2: Checking Circuit 729 (RD/WH) For B+

  Courtesy of FORD MOTOR CO.
• Is the voltage B+? 

Result / Action to Take 

Yes 

GO to H3.

No 

REPAIR circuit 729 (RD/WH) for an open. TEST the system for normal operation.

Test Step 

H3 CHECK CIRCUIT 1040 (RD/BK) FOR B+ 

• Key in ON position.
• Measure the voltage between the DATC module C228b-22, circuit 1040 (RD/BK) and ground.
  Fig 3: Checking Circuit 1040 (RD/BK) For B+

  Courtesy of FORD MOTOR CO.
• Is the voltage B+? 

Result / Action to Take 

Yes 

REFER to MODULE COMMUNICATIONS NETWORK to diagnose a network concern.

No 

REPAIR circuit 1040 (RD/BK) for an open. TEST the system for normal operation.