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

WARNING: This page is about a different car, the 2004 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?
  1. Yes : GO to A2.
  2. 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?
  1. Yes : GO to A3.
  2. 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: Checking Circuit 31-FA10 (BK) For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
  1. Yes : GO to A4.
  2. 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: Checking Circuit 29-FA10 (OG/GN) For Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
  1. Yes : GO to A5.
  2. 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 C228a-3, circuit 20-FA10 (PK/OG), harness side and ground.
  
  Fig 3: Checking Circuit 20-FA10 (PK/OG) For Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
  1. Yes : Diagnose the network concern.
  2. No : REPAIR circuit 20-FA10 (PK/OG). TEST the system for normal operation.