Ford 2003 Mustang Workshop Manual page 3473

If equipped with M/T, measure the resistance between
reversing lamp switch C169, Circuit 140 (BK/PK), harness
side and ground.
Is the resistance less than 5 ohms?
R3 CHECK REVERSING LAMPS GROUND
Disconnect: Inoperative Reversing Lamp.
Measure the resistance between LH reversing lamp C451,
Circuit 1205 (BK), or RH reversing lamp C461, Circuit
1205 (BK), harness side and ground.
Is the resistance less than 5 ohms?
PINPOINT TEST S: THE INDIVIDUAL REVERSING LAMP IS
INOPERATIVE
S1 CHECK REVERSING LAMPS GROUND
Key in OFF position.
Disconnect: Inoperative Reversing Lamp.
Measure the resistance between LH reversing lamp C451, Circuit
1205 (BK), or RH reversing lamp C461, Circuit 1205 (BK),
harness side and ground.
Test Step
system for normal operation.
No
GO to R3 .
Yes
REPAIR Circuit 140 (BK/PK)
for open. TEST the system for
normal operation.
No
REPAIR the circuit. TEST the
system for normal operation.
Result / Action to
Take
Yes
REPAIR Circuit 140
(BK/PK) for open.
TEST the system for
normal operation.