PINPOINT TEST I: THE EATC SYSTEM IS INOPERATIVE, INTERMITTENT OR INCORRECT OPERATION
Test Step
Result / Action to Take
I1 VERIFY AUTOMATIC OPERATION
Ignition ON.
With the engine running, press the AUTOMATIC button.
Does the indicator above the AUTO button illuminate and the selected temperature for both
the driver and passenger appear in the display window?
Yes
GO to
I2
.
No
GO to
I11
.
I2 CARRY OUT THE EATC MODULE SELF-TEST
Ignition ON.
Carry out the EATC module self-test. Refer to the Electronic Automatic Temperature Control Module
Self-Test in this section. Record the DTCs displayed, if any.
Were any DTCs displayed as a result of the EATC self-test?
Yes
REFER to the EATC Module Diagnostic Trouble Code (DTC) Index.
CARRY OUT the necessary diagnosis and REPAIR as required.
No
GO to
I3
.
I3 CHECK THE VACUUM FLUORESCENT DISPLAY
Exit self-test by pressing the DEFROST button. Observe the button indicators and function symbols
displayed on the vacuum fluorescent display while changing the temperature, blower speed and
functions.
Are the display and indicators correct and complete without any missing elements?
Yes
GO to
I4
.
No
INSTALL a new EATC module. TEST the system for normal
operation.
I4 CHECK THE BLOWER MANUAL OVERRIDE OPERATION
Press the blower motor speed override control fully up and fully down.
Does the blower motor speed increase from low speed to high and high speed to low?
Yes
GO to
I5
.
No
If the blower motor is inoperative,
GO to Pinpoint Test M
.
If the blower motor does not operate correctly,
GO to Pinpoint Test
N
.
I5 VERIFY THE DEFROST OVERRIDE OPERATION
Press the override button for DEFROST operation.
Is outside air being discharged from the windshield defroster nozzle and the side window
demisters?
Yes
GO to
I6
.
No
GO to Pinpoint Test F
.
I6 VERIFY THE FLOOR OVERRIDE OPERATION
Press the override button for FLOOR operation.
Is outside air being discharged from the floor duct?
Yes
GO to
I7
.
No
GO to Pinpoint Test F
.
I7 VERIFY THE PANEL OVERRIDE OPERATION
Press the override button for PANEL operation.
Is outside air being discharged from the instrument panel registers?
Yes
GO to
I8
.
No
GO to Pinpoint Test F
.
I8 VERIFY THE A/C CLUTCH DOES NOT ENGAGE IN THE PANEL MODE
Press the override button for PANEL operation.
Verify that the A/C request button indicator is not illuminated. If illuminated, press the A/C request
button to turn the A/C indicator off and disengage the A/C compressor clutch.
Does the A/C clutch engage when the PANEL override button is pressed?
Yes
GO to Pinpoint Test L
.
No
GO to
I9
.
I9 VERIFY THE RECIRC OVERRIDE OPERATION
Press the PANEL and RECIRC override buttons.
Is recirculated air being discharged from the instrument panel registers?
Yes
GO to
I10
.
No
GO to Pinpoint Test E
.
I10 VERIFY A/C CLUTCH ENGAGEMENT IN THE A/C MODE
Make sure the ambient air temperature is above 5°C (41°F).
Press the override button for A/C operation.
Does the A/C clutch engage when the PANEL and A/C override button is pressed?
Yes
The test is complete. The system is functioning normally.
No
GO to Pinpoint Test K
.
I11 CHECK THE EATC MODULE FUNCTIONS
Press each function button and observe the display.
Does the EATC carry out and display any functions?
Yes
GO to
I14
.
No
GO to
I12
.
I12 CHECK THE VOLTAGE TO THE EATC
Ignition OFF.
Disconnect: EATC C228b.
Ignition ON.
Measure the voltage between ground EATC module C228b-11, circuit 1655 (RD/YE).
Yes
GO to
I13
.
No
VERIFY the central junction box (CJB) fuse 15 (10A) and fuse 27
(10A) is OK. If OK, REPAIR the affected circuit. TEST the system for
normal operation.
Page 28 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...
