Pinpoint Test F: No Communication With The Electronic Automatic Temperature Control (EATC) Module

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

F1 CHECK CIRCUIT GD116 (BK/VT) FOR AN OPEN
- Key in OFF position.
- Disconnect: DATC C2356a or EATC Module C228a.
- Measure the resistance between DATC C2356a-1 or EATC module C228a-1, circuit GD116 (BK/VT) and ground.
  
  Fig 1: Checking Circuit GD116 (BK/VT) For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : GO to F2.

No : REPAIR circuit GD116 (BK/VT). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
F2 CHECK CIRCUITS SBP07 (WH/RD) AND CBP20 (YE/VT) FOR AN OPEN
- Key in ON position.
- Measure the voltage between DATC C2356a-26 or EATC module C228a-26, circuit SBP07 (WH/RD), DATC C2356a-19 or EATC module C228a-19, circuit CBP20 (YE/VT) and ground.
  
  Fig 2: Checking Circuits SBP07 (WH/RD) And CBP20 (YE/VT) For An Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes : GO to MODULE COMMUNICATIONS NETWORK to diagnose the network concern.

No : VERIFY smart junction box (SJB) fuses 13 (7.5A) and 27 (7.5A) are OK. If OK, REPAIR circuit SBP07 (WH/RD) or CBP20 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.