Pinpoint Test N: The Blower Motor Does Not Operate Correctly
Refer to Wiring Diagrams Cell
55
, Automatic Climate Control System for schematic and connector information.
Normal Operation
Under normal operation, the blower motor relay coil receives voltage through circuit 181 (BN/OG). The coil receives ground from the electronic automatic temperature control (EATC)
Is the voltage greater than 10 volts?
M10 CHECK THE EATC MODULE OUTPUT
Ignition ON.
Measure the voltage between blower motor relay socket pin 86, circuit 181 (BN/OG) and socket pin 85,
circuit 364 (BK/LG).
Is the voltage greater than 10 volts?
Yes
INSTALL a new blower motor relay. TEST the system for
normal operation.
No
GO to
M11
.
M11 CHECK CIRCUIT 364 (BK/LG) FOR SHORT TO VOLTAGE
Ignition OFF.
Disconnect: EATC Module C228b.
Ignition ON.
Measure the voltage between blower motor relay socket pin 85, circuit 364 (BK/LG) and ground.
Is voltage present?
Yes
REPAIR circuit 364 (BK/LG) for a short to voltage. TEST the
system for normal operation.
No
GO to
M12
.
M12 CHECK CIRCUIT 364 (BK/LG) FOR AN OPEN
Ignition OFF.
Measure the resistance between EATC module C228b-9, circuit 364 (BK/LG) and blower motor relay
socket pin 85, circuit 364 (BK/LG).
Is the resistance less than 5 ohms?
Yes
GO to
M13
.
No
REPAIR circuit 364 (BK/LG) for an open. TEST the system for
normal operation.
M13 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.
Page 38 of 45
2006 Town Car Workshop Manual
12/30/2011
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