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

WARNING: This page is about a different car, the 2004 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

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.

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.

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.

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