Pinpoint Test F: DTC B1263 or B1264 — Panel/Defrost or Floor Door Failure
Refer to Wiring Diagrams Cell
55
, Automatic Climate Control System for schematic and connector information.
Normal Operation
The panel/defrost and floor door actuator motors both work the same. Each door actuator motor has 2 circuits that the HVAC module applies voltage to and reverses the polarity to reverse
door actuator motor rotation. The panel/defrost door actuator motor circuits are 1379 (PK/LB) and 1380 (TN/YE); the floor door actuator motor circuits are 1375 (PK/YE) and 1376 (BK/LB).
Each door actuator motor has a position sensor that supplies a voltage to the HVAC module to indicate door position. Both door actuator motors receive reference voltage (5V) on circuit
436 (RD/LG) and a sensor ground on circuit 438 (RD/WH). Position signals are provided by the panel/defrost door actuator motor on circuit 1123 (YE/WH) and circuit 1130 (PK/LG) by the
floor door actuator motor.
DTC B1263 (Servo Motor Vent Circuit Failure) — The module senses no change in actuator feedback voltage when the actuator motor has been energized.
DTC B1264 (Servo Motor Foot Circuit Failure) — The module senses no change in actuator feedback voltage when the actuator motor has been energized.
This pinpoint test is intended to diagnose the following:
Wiring, terminals or connectors
Panel/defrost or floor door actuator
HVAC module
Stuck or bound linkage or door
PINPOINT TEST F: DTC B1263 OR B1264 — PANEL/DEFROST OR FLOOR DOOR FAILURE
Is the resistance less than 5 ohms?
E21 CHECK CIRCUIT 436 (RD/LG) AND CIRCUIT 435 (YE/LB) FOR A SHORT
TOGETHER
Measure the resistance between EATC module C228b-8, circuit 436 (RD/LG) and
EATC module C228b-3, circuit 435 (YE/LB).
Is the resistance less than 5 ohms?
Yes
REPAIR circuits 436 (RD/LG) and circuit 435 (YE/LB) for a short together. CLEAR the
DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new door actuator. REFER to
Section 412-01
. CLEAR the DTCs. REPEAT
the self-test. TEST the system for normal operation.
E22 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
F1 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
Disconnect: HVAC Module C228a.
Disconnect: HVAC Module C228b.
Measure the resistance between HVAC module C228b-8, circuit 436 (RD/LG),
harness side and HVAC module C228a-20, circuit 438 (RD/WH), harness side.
Is the resistance greater than 500 ohms?
Yes
If diagnosing
DTC B1263
, GO to
F3
.
If diagnosing
DTC B1264
, GO to
F4
.
No
GO to
F2
.
Page 20 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...
