Pinpoint Tests
Pinpoint Test A: DTC B2266 Or DTC B2267 — Blend Door Failure Or Short
Refer to Wiring Diagrams Cell
55
, Automatic Climate Control System for schematic and connector information.
Normal Operation
Under normal operation, the driver side (LH) and passenger side (RH) temperature blend door actuator motors are supplied voltage or ground on circuit 245 (BN/LG) (LH) or circuit 1125
(BN) (RH), depending on desired actuator rotation, by the electronic automatic temperature control (EATC) module. The EATC module then supplies the appropriate voltage or ground to
the other side of the actuator motor on circuit 246 (VT) (LH) or circuit 1124 (WH) (RH).
The driver side (LH) and passenger side (RH) temperature blend door actuator feedback resistors are supplied a ground from the EATC module by circuit 438 (RD/WH) and a 5 volt
reference voltage on circuit 436 (RD/LG). The EATC module reads the voltage on circuit 437 (RD/WH) (LH) or circuit 1122 (RD) (RH) to determine the actuator position by the position of
the actuator feedback resistor wiper arm.
Possible Causes
An open, short to voltage, ground or together in circuits 245 (BN/LG), 246 (VT), 436 (RD/LG), 437 (RD/WH), 438 (RD/WH), 1124 (WH) or 1125 (BN)
Driver side (LH) or passenger side (RH) temperature blend door actuator
Electronic automatic temperature control (EATC) module
Stuck or bound linkage or door
Low refrigerant level
A/C cycling switch
Temperature blend
door actuator control
Insufficient, erratic or no heat
Low engine coolant
level
Engine overheating
Plugged or partially
plugged heater core
Temperature blend
door binding or stuck
A/C electric blend door
actuator
Blend door circuit
open/shorted
GO to Pinpoint Test J
.
The air conditioning (A/C) is
inoperative
Fuse(s)
A/C clutch relay
Circuitry short or open
A/C cycling switch
A/C system discharged
or low charge
A/C compressor clutch
A/C pressure
transducer
EATC module
PCM
GO to Pinpoint Test K
.
The air conditioning (A/C) is
always on
Circuitry short or open
EATC module
A/C clutch relay
A/C compressor clutch
A/C evaporator core
temperature sensor
GO to Pinpoint Test L
.
The blower motor is inoperative
Fuse(s)
Circuitry open or
shorted
Blower motor
Blower motor speed
control
Blower motor relay
GO to Pinpoint Test M
.
The blower motor does not
operate correctly
Blower motor speed
control
EATC module
Circuit short or open
GO to Pinpoint Test N
.
The rear audio and climate
control switch is
inoperative/does not operate
correctly.
Fuse
Circuitry short or open
Rear audio/climate
control switch
Rear audio/climate
control module
Audio control module
(ACM)
EATC module
GO to Pinpoint Test O
.
The temperature set point does
not repeat after turning the
ignition switch off
Fuse
Circuitry short or open
EATC module
VERIFY central junction box (CJB) fuse 27 (10A) is OK. If OK, CHECK circuit 1566
(RD/YE) for an open and REPAIR as necessary. If OK, INSTALL a new EATC module.
The electronic automatic
temperature control is
inoperative/does not operate
correctly — EATC
Temperature blend
door/actuator
broken/binding
EATC module
CHECK the temperature blend doors/actuators for a binding or broken condition. If no
condition is found, INSTALL a new EATC module.
The temperature display will not
switch between Celsius and
Fahrenheit
EATC module
INSTALL a new EATC/EATC module.
Inaccurate external temperature
display
EATC module
REFER to description and operation of the EATC External Temperature Display. If the
external temperature display is not operating as described and no DTC is present,
CARRY OUT the ambient temperature sensor component test in this section. If the
sensor tests OK, INSTALL a new EATC module. REFER to
Section 412-01
. TEST the
system for normal operation.
Page 4 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...
