Ford 2003 Mustang Workshop Manual page 3071

Disconnect: CCRM C1262.
Measure the resistance of CCRM C1262-18, circuit 1205
(BK), harness side and ground.
Is the resistance reading less than 5 ohms?
C21 CHECK CIRCUIT 20 (WH/LB) AT THE CONSTANT
CONTROL RELAY MODULE
Key in ON position.
Measure the voltage at the CCRM C1262-13, circuit 20
(WH/LB), harness side and ground.
Is the voltage reading greater than 10 volts?
C22 CHECK THE POWER TO THE A/C CLUTCH
Key in OFF position.
Connect: CCRM 1262.
Disconnect: A/C Clutch C100.
Turn the function selector to the A/C position.
Measure the voltage at the A/C clutch C100, circuit 347
(BK/YE), harness side and ground.
GO to C21 .
No
REPAIR circuit 1205 (BK) for
an open. TEST the system for
normal operation.
Yes
GO to C22 .
No
REPAIR circuit 20 (WH/LB) for
an open. TEST the system for
normal operation.
Yes
GO to C24 .
No
GO to C23 .