Ford 2003 Mustang Workshop Manual page 3454

Pinpoint Tests
PINPOINT TEST G: THE STOPLAMPS ARE INOPERATIVE
G1 CHECK CIRCUIT 10 (LG/RD) FOR AN OPEN
Disconnect: Brake Pedal Position (BPP) Switch C278.
Measure the voltage between the BPP switch C278,
circuit 10 (LG/RD), harness side and ground.
Is the voltage greater than 10 volts?
G2 CHECK THE CIRCUIT 810 (RD/LG) FOR AN OPEN
Connect a 10A fused jumper wire between C278, circuit
10 (LG/RD), harness side and C278, circuit 810 (RD/LG),
harness side.
Do the stoplamps illuminate?
PINPOINT TEST H: ONE OR MORE STOPLAMPS ARE INOPERATIVE
H1 CHECK THE VOLTAGE TO THE INOPERATIVE STOPLAMP
Disconnect: Inoperative Stoplamp.
If a rear stoplamp is inoperative, measure the voltage between
the inoperative stoplamp connector circuit 9 (LG/OG) (LH) or
circuit 5 (OG/LB) (RH), harness side and ground, while pressing
the brake pedal.
Test Step
Test Step
Result / Action to Take
Yes
GO to G2 .
No
REPAIR the circuit. TEST the
system for normal operation.
Yes
INSTALL a new BPP switch.
REFER to Lamp Switch—
Brake Pedal Position (BPP)
this section. TEST the system
for normal operation.
No
REPAIR circuit 810 (RD/LG)
or 569 (DG) as necessary.
TEST the system for normal
operation.
Result / Action to
Take
Yes
REPAIR circuit 1205
(BK). TEST the system
for normal operation.
No
If high mounted
stoplamp, REPAIR
circuit 569 (DG). TEST
the system for normal
in