Ford 2003 Mustang Workshop Manual page 696

Is the resistance less than 5 ohms between the instrument
cluster and traction control switch and greater than 10,000
ohms between instrument cluster and ground?
M2 CHECK CIRCUIT 489 (PK/BK) FOR AN OPEN
Key in ON position.
Measure the voltage between traction control switch C239 Pin 3,
Circuit 489 (PK/BK), harness side and ground.
Is the voltage greater than 10 volts?
M3 CHECK THE TRACTION CONTROL SWITCH INDICATOR
Key in OFF position.
Connect: Traction Control Switch C239.
Key in ON position.
Momentarily connect a fused (10A) jumper wire between instrument
cluster C251 Pin 8, Circuit 960 (BK/LB), harness side and ground,
while observing the traction control switch indicator.
Does the traction control switch indicator illuminate?
Yes
GO to M3 .
No
REPAIR the circuit.
TEST the system
for normal
operation.
Yes
INSTALL a new
instrument cluster;
REFER to Section
413-01 . TEST the
system for normal
operation.
No
INSTALL a new
traction control
switch. TEST the
system for normal
operation.