K1 CHECK THE A/C PRESSURE PCM PID
Ignition ON.
Enter the following diagnostic mode on the scan tool: A/C Pressure PCM PID.
With the manifold gauge set connected, compare the pressure readings of the manifold gauge set and the A/C pressure
PID.
Are the pressure values of the manifold gauge set and the A/C pressure PID similar?
Yes
GO to
K2
.
No
INSTALL a new A/C pressure transducer. TEST
the system for normal operation.
K2 CHECK THE A/C REQUEST (ACCS) PCM PID WITH THE A/C ON
Start the engine.
Enter the following diagnostic mode on the scan tool: A/C REQUEST PCM PID.
Press the PANEL and A/C manual override buttons on the EATC module.
Does the A/C REQUEST PCM PID read ON?
Yes
GO to
K4
.
No
GO to
K3
.
K3 CHECK THE A/C SWITCH EATC PID WITH THE A/C ON
Enter the following diagnostic mode on the scan tool: A/C SWITCH EATC PID.
Press the PANEL and A/C manual override buttons on the EATC module.
Does the A/C SWITCH EATC PID read ON?
Yes
GO to
K5
.
No
GO to
K16
.
K4 CHECK THE A/C CLUTCH RELAY PID WITH THE A/C ON
Enter the following diagnostic mode on the scan tool: PCM A/C CLUTCH RELAY PID.
Does the PCM A/C CLUTCH RELAY PID read ON?
Yes
GO to
K8
.
No
GO to
K17
.
K5 CHECK CYCLING SWITCH VOLTAGE
Ignition OFF.
Disconnect: A/C Cycling Switch C1081.
Ignition ON.
Measure the voltage between cycling switch C1081-4, circuit 348 (VT)/1040 (RD/BK) and ground.
Is the voltage greater than 10 volts?
Yes
GO to
K6
.
No
VERIFY the central junction box (CJB) fuse 31
(10A) is OK. If OK, REPAIR circuit 348
(VT)/1040 (RD/BK) for an open. TEST the
system for normal operation.
K6 CHECK CYCLING SWITCH
Ignition OFF.
Measure the resistance between the cycling switch terminals.
Is the resistance less than 21 ohms?
Yes
GO to
K7
.
No
INSTALL a new cycling switch. TEST the system
for normal operation.
K7 CHECK CIRCUIT 883 (PK/LB) FOR AN OPEN
Disconnect: PCM C175B.
Measure the resistance between A/C cycling switch C1081-1, circuit 883 (PK/LB) and PCM C175B-3, circuit 883 (PK/LB).
Is the resistance less than 5 ohms?
Yes
GO to
K17
.
No
REPAIR circuit 883 (PK/LB) for an open. TEST
the system for normal operation.
K8 CHECK THE VOLTAGE AT THE A/C COMPRESSOR CLUTCH FIELD COIL
Ignition OFF.
Disconnect: A/C Compressor Clutch Field Coil C100.
Start the engine.
Press the PANEL and A/C manual override buttons on the EATC module.
Measure the voltage between A/C compressor clutch field coil C100-1, circuit 321 (GY/WH) and ground.
Yes
GO to
K9
.
No
GO to
K11
.
Page 31 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...
