Ford 2003 Mustang Workshop Manual page 3652

Measure the resistance between passenger exterior rear view
mirror C622 pin C, circuit 542 (YE), harness side and exterior
rear view mirror control C527 pin 6, circuit 542 (YE), harness
side.
Is the resistance less than 5 ohms?
PINPOINT TEST B: A SINGLE MIRROR IS INOPERATIVE
B1 CHECK THE COMMON FEED INPUT
Disconnect: Exterior Rear View Mirror C516 (Driver) C622
(Passenger).
Disconnect the inoperative exterior rear view mirror C516 driver
side or C622 passenger side.
Measure the voltage between driver exterior rear view mirror C516
pin C, circuit 542 (YE), harness side and ground; or between
passenger exterior rear view mirror C622 pin C, circuit 542 (YE),
harness side and ground.
Select the inoperative side and actuate the exterior rear view
mirror control to the down position, then the right position.
Are the voltages greater than 10 volts?
B2 CHECK CIRCUIT 542 (YE) FOR AN OPEN
Disconnect: Exterior Rear View Mirror Control C527.
Measure the resistance between exterior rear view mirror control
C527 pin 6, circuit 542 (YE), harness side and driver exterior rear
view mirror C516 pin C, circuit 542 (YE), harness side; or between
exterior rear view mirror control C527 pin 6, circuit 542 (YE),
harness side and passenger exterior rear view mirror C622 pin C,
circuit 542 (YE), harness side.
Test Step
Yes
INSTALL a new exterior
rear view mirror control.
REFER to Switch—
Exterior Rear View
Mirror Control in this
section.
No
REPAIR the circuit.
TEST the system for
normal operation.
Result / Action to
Take
Yes
GO to B3 .
No
GO to B2 .
Yes
INSTALL a new
exterior rear view
mirror control.
REFER to Switch—
Exterior Rear View
Mirror Control in this
section. TEST the
system for normal
operation.