Pinpoint Test A: No Communication With The Dual Automatic Temperature Control (DATC) Module

WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK THE CJB FUSE 220 (10A)
- Key in OFF position.
- Turn the headlights on.
- Does the DATC backlighting come on?
- Yes : GO to A2.
- No : INSTALL a new fuse. TEST the system for normal operation.
A2 CHECK THE CJB FUSE 214 (10A)
- Key in ON position.
- Does the vacuum fluorescent (VF) display and indicators come on when DATC buttons are pushed?
- Yes : GO to A3.
- No : INSTALL a new fuse. TEST the system for normal operation.
A3 CHECK CIRCUIT 31-FA10 (BK) FOR AN OPEN
- Disconnect: DATC Module C228a.
- Measure the resistance between DATC module C228a-2, circuit 31-FA10 (BK), harness side and ground.
  
  Fig 1: Measuring The Resistance Between DATC Module C228a-2, Circuit 31-FA10 (BK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to A4.
- No : REPAIR circuit 31-FA10 (BK). TEST the system for normal operation.
A4 CHECK CIRCUIT 29-FA10 (OG/GN) FOR VOLTAGE
- Key in ON position.
- Measure the voltage between DATC module C228a-14, circuit 29-FA10 (OG/GN), harness side and ground.
  
  Fig 2: Measuring The Voltage Between DATC Module C228a-14, Circuit 29-FA10 (OG/GN), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to A5.
- No : REPAIR circuit 29-FA10 (OG/GN). TEST the system for normal operation.
A5 CHECK CIRCUIT 20-FA10 (PK/OG) FOR VOLTAGE
- Key in ON position.
- Measure the voltage between DATC module C 28a-3, circuit 20-FA10 (PK/OG), harness side and ground.
  
  Fig 3: Measuring The Voltage Between DATC Module C 28a-3, Circuit 20-FA10 (PK/OG), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : Diagnose the network concern.
- No : REPAIR circuit 20-FA10 (PK/OG). TEST the system for normal operation.