F2 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
NOTE:
Access to the connector in the following step is difficult. Before
performing this step, visually inspect the actuator and its harness for obvious
damage. If no damage is evident, proceed with the test.
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.
While measuring the resistance above, disconnect the following components one
at a time, in order. Stop disconnecting components if the measured resistance
rises above 500 ohms.
Air inlet door actuator C289
LH blend door actuator C2092
RH blend door actuator C2092
Did the resistance rise above 500 ohms?
Yes
INSTALL a new actuator (the last one to be disconnected). TEST the system for normal
operation.
No
Visually INSPECT the harness between the actuators and the HVAC module for obvious
damage. REPAIR as necessary. If no damage is evident, INSTALL a new floor door
actuator and panel/defrost door actuator. If a new actuator is installed, CONNECT the
actuator electrical connectors before the HVAC module connectors. This will allow the
new actuator to be calibrated when the HVAC module is reconnected. CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
F3 CHECK POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE
Measure the
low-side
resistance between HVAC module C228a-20, circuit 438
(RD/WH), harness side and HVAC module C228b-15, circuit 1123 (YE/WH),
harness side.
Measure the
high-side
resistance between HVAC module C228b-8, circuit 436
(RD/LG), harness side and HVAC module C228b-15, circuit 1123 (YE/WH),
harness side.
Is the resistance between 250 and 5,500 ohms?
Yes
GO to
F5
.
No
CARRY OUT the Panel/Defrost Door Actuator Component Test in this section. If a new
actuator is installed, CONNECT the actuator electrical connector before the HVAC
module connector(s). This will allow the new actuator to be calibrated when the HVAC
module is reconnected. If the actuator tests OK and:
If the
low-side
resistance only is greater than 5,500 ohms, REPAIR circuit 438 (RD/WH)
for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal
operation.
If the
low-side
resistance only is less than 250 ohms, REPAIR circuits 1123 (YE/WH) and
438 (RD/WH) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the
system for normal operation.
If the
high-side
resistance only is greater than 5,500 ohms, REPAIR circuit 436 (RD/LG)
for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal
operation.
If the
high-side
resistance only is less than 250 ohms, REPAIR circuits 1123 (YE/WH)
and 436 (RD/LG) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the
system for normal operation.
If both the
high-side and low-side
resistance is greater than 5,500 ohms, REPAIR circuit
1123 (YE/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system
for normal operation.
F4 CHECK POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE
Measure the
low-side
resistance between HVAC module C228a-20, circuit 438
(RD/WH), harness side and HVAC module C228b-14, circuit 1130 (PK/LG),
harness side.
Measure the
high-side
resistance between HVAC module C228b-8, circuit 436
(RD/LG), harness side and HVAC module C228b-14, circuit 1130 (PK/LG),
harness side.
Yes
GO to
F5
.
No
CARRY OUT the Floor Door Actuator Component Test in this section. If a new actuator is
installed, CONNECT the actuator electrical connector before the HVAC module connector
(s). This will allow the new actuator to be calibrated when the HVAC module is
reconnected. If the actuator tests OK and:
If the
low-side
resistance only is greater than 5,500 ohms, REPAIR circuit 438 (RD/WH)
for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal
operation.
If the
low-side
resistance only is less than 250 ohms, REPAIR circuits 1130 (PK/LG) and
438 (RD/WH) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the
system for normal operation.
If the
high-side
resistance only is greater than 5,500 ohms, REPAIR circuit 436 (RD/LG)
for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal
operation.
If the
high-side
resistance only is less than 250 ohms, REPAIR circuits 1130 (PK/LG)
and 436 (RD/LG) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the
system for normal operation.
If both the
high-side and low-side
resistance is greater than 5,500 ohms, REPAIR circuit
1130 (PK/LG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for
normal operation.
Page 21 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...
