Ford 2003 Mustang Workshop Manual page 3447

Measure the resistance between headlamp switch C205 Pin
H, Circuit 15 (RD/YE), harness side and multifunction switch
C202a Pin 15, Circuit 15 (RD/YE), harness side.
Is the resistance less than 5 ohms?
A3 CHECK THE VOLTAGE TO THE MULTIFUNCTION SWITCH
Place the headlamp switch in the ON position.
Measure the voltage between multifunction switch C202a
Pin 15, Circuit 15 (RD/YE), harness side and ground.
Is the voltage greater than 10 volts?
PINPOINT TEST B: THE LOW BEAMS ARE INOPERATIVE
B1 CHECK THE VOLTAGE TO CJB FUSE 4 (7.5A) AND CJB
FUSE 10 (7.5A)
Key in OFF position.
Place the multifunction switch in the low beam position.
Remove Fuse 4 (7.5A) and Fuse 10 (7.5A) from the CJB.
Place the headlamp switch in the ON position.
Measure the voltage between the following CJB fuse
terminals and ground:
Fuse 4 connector.
Fuse 10 connector.
Test Step
RECONNECT headlamp
switch C205. GO to A3
No
REPAIR the circuit. TEST
the system for normal
operation.
Yes
INSTALL a new
multifunction switch;
REFER to Section 211-05
TEST the system for
normal operation.
No
INSTALL a new headlamp
switch; REFER to Lamp
Switch—Headlamp in this
section. TEST the system
for normal operation.
Result / Action to Take
Yes
Go To Pinpoint Test D
No
GO to B2 .
.
.
.