module through circuit 364 (BK/LG) if any position but OFF is selected. Voltage is supplied to the relay switch contact through circuit 181 (BN/OG). When the relay coil is energized, voltage
is delivered to the blower motor through circuit 371 (PK/WH). Ground for the motor is provided through circuit 515 (OG/RD) from the blower control module. Ground for the blower control
module is provided by circuit 57 (BK).
The blower motor control module receives a 1-2 volt signal from the EATC module through circuit 752 (YE/RD) to determine the desired blower motor speed. The EATC module receives a
feedback voltage from the blower motor control module through circuit 260 (RD/OG) to determine actual blower motor speed. When the highest blower motor setting is selected, the EATC
module sends 12 volts to the blower control module through circuit 754 (LG/WH).
Possible Causes
An open, short to voltage, ground or together in circuits 260 (RD/OG), 752 (YE/RD) or 754 (LG/WH)
A short to ground in circuit 515 (OG/RD)
Blower motor control module
Electronic automatic temperature control (EATC) module
PINPOINT TEST N: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY
Test Step
Result / Action to Take
N1 CHECK CIRCUIT 515 (OG/RD) FOR A SHORT TO GROUND
Ignition OFF.
Disconnect: Blower Motor Speed Control C1308.
Ignition ON.
Press the PANEL button on the EATC module. Adjust the blower motor setting to LO
and then to HI.
Does the blower motor operate?
Yes
REPAIR circuit 515 (OG/RD) for a short to ground. TEST the system for normal
operation.
No
GO to
N2
.
N2 CHECK THE BLOWER MOTOR SPEED CONTROL
Ignition OFF.
Connect: Blower Motor Speed Control C1308.
Disconnect: EATC Module C228a.
Disconnect: Blower Motor Relay.
Connect a fused jumper wire between blower motor relay socket pin 30, circuit 181
(BN/OG) and pin 87, circuit 371 (PK/WH).
Ignition ON.
Does the blower motor operate?
Yes
INSTALL a new blower motor speed control. TEST the system for normal operation.
No
GO to
N3
.
N3 CHECK THE BLOWER MOTOR SPEED CONTROL CIRCUITS FOR AN OPEN
Ignition OFF.
Disconnect: Blower Motor Speed Control C1308.
Measure the resistance between blower motor speed control:
C1308-1, circuit 260 (RD/OG) and EATC module C228a-3, circuit 260
(RD/OG).
C1308-2, circuit 752 (YE/RD) and EATC module C228a-16, circuit 752
(YE/RD).
C1308-3, circuit 754 (LG/WH) and EATC module C228a-8, circuit 754
(LG/WH).
Are the resistances less than 5 ohms?
Yes
GO to
N4
.
No
REPAIR the affected circuit for an open. TEST the system for normal operation.
N4 CHECK THE BLOWER MOTOR SPEED CONTROL CIRCUITS FOR A SHORT TO
VOLTAGE
Ignition ON.
Measure the voltage between blower motor speed control:
C1308-1, circuit 260 (RD/OG) and ground.
C1308-2, circuit 752 (YE/RD) and ground.
C1308-3, circuit 754 (LG/WH) and ground.
Yes
REPAIR the affected circuit for a short to voltage. TEST the system for normal
operation.
No
GO to
N5
.
Page 39 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...