Ford 2003 Mustang Workshop Manual page 3325

CJB FUSE 28 (15A)
Disconnect: CJB Fuse 28 (15A).
Measure the voltage between CJB fuse 28 (15A), pin 1,
harness side and ground while cycling the ignition switch
through all positions.
Is the voltage greater than 10 volts in the RUN and START
positions only?
B5 CHECK GEM INPUT VOLTAGE FROM IGNITION SWITCH AT
CJB FUSE 32 (15A)
Disconnect: CJB Fuse 32 (15A).
Measure the voltage between CJB fuse 32 (15A), pin 1,
harness side and ground while cycling the ignition switch
through all positions.
Is the voltage greater than 10 volts in the RUN and ACC
positions only?
B6 CHECK GEM VOLTAGE INPUT CIRCUITS FOR OPEN —
IGNITION SWITCH CIRCUIT 911 (WH/LG)
Disconnect: CJB Fuse 28 (15A).
Disconnect: GEM C201e.
Insert the ignition key. Measure the resistance between GEM
C201e pin 8, circuit 911 (WH/LG), harness side and CJB Fuse
28 (15A) pin 2, circuit 911 (WH/LG), harness side.
Is the resistance less than 5 ohms?
B7 CHECK GEM VOLTAGE INPUT CIRCUITS FOR OPEN —
IGNITION SWITCH CIRCUIT 1002 (BK/PK)
Yes
GO to B5 .
No
REPAIR the CJB.
REPEAT the self-test.
CLEAR the DTCs.
Yes
GO to B6 .
No
REPAIR the CJB.
REPEAT the self-test.
CLEAR the DTCs.
Yes
GO to B7 .
No
REPAIR the circuit.
REPEAT the self-test.
CLEAR the DTCs.