Pinpoint Test J: Insufficient, Erratic Or No Heat
Normal Operation
Under normal operation, warm coolant flows from the engine through the heater core and back to the engine.
Possible Causes
Plugged heater core
Coolant level
Temperature blend door
PINPOINT TEST J: INSUFFICIENT, ERRATIC OR NO HEAT
Measure the voltage between ground EATC module C228b-22, circuit 1812 (BN/WH).
Are the voltages greater than 10 volts?
I13 CHECK THE GROUND CIRCUIT TO THE EATC
Ignition OFF.
Disconnect: EATC C228a.
Measure the resistance between EATC module C228a-2, circuit 676 (PK/OG) and ground.
Is the resistance less than 5 ohms?
Yes
GO to
I14
.
No
REPAIR circuit 676 (PK/OG) for an open. TEST the system for
normal operation.
I14 CHECK MODULE CONNECTION
Carry out the Electronic Automatic Temperature Control (EATC) Module Cold Boot Process.
Carry out the EATC on-demand self test.
Operate the system.
Does the concern return?
Yes
INSTALL a new EATC module. REFER to
Section 412-01
. TEST the
system for normal operation.
No
The system is operating correctly at this time. The concern may have
been caused by a loose or corroded connector. CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
Test Step
Result / Action to Take
J1 CHECK FOR CORRECT ENGINE COOLANT LEVEL
Ignition OFF.
Check the engine coolant level when hot and when cold.
Is the engine coolant at the correct level (hot and cold)?
Yes
GO to
J3
.
No
GO to
J2
.
J2 CHECK THE COOLANT SYSTEM INCLUDING THE RADIATOR CAP FOR LEAKS
Fill the engine cooling system to the specified level.
Pressure check the engine cooling system, including the radiator cap. Refer to
Section 303-03
.
It is not necessary to check the components separately at this time.
Does the engine cooling system, including the radiator cap, hold pressure?
Yes
GO to
J3
.
No
REPAIR the cooling system leak. TEST the system for normal operation.
J3 CHECK FOR HOT WATER TO THE HEATER CORE INLET HOSE
Yes
Page 29 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...