Ford 2003 Mustang Workshop Manual page 3653

Is the resistance less than 5 ohms?
B3 CHECK THE UP/DOWN INPUT
Measure the voltage between driver exterior rear view mirror C516
pin B, circuit 541(DB), harness side and ground; or between
passenger exterior rear view mirror C622 pin A, circuit 544 (VT),
harness side and ground.
Actuate the exterior rear view mirror control to the up position.
Are the voltages greater than 10 volts?
B4 CHECK CIRCUIT 541 (DB) FOR AN OPEN
Disconnect: Exterior Rear View Mirror Control C527.
Measure the resistance between exterior rear view mirror control
C527 pin 3, circuit 541 (DB), harness side and driver exterior rear
view mirror C516 pin B, circuit 541 (DB), harness side.
Is the resistance less than 5 ohms?
B5 CHECK CIRCUIT 544 (VT) FOR AN OPEN
Disconnect: Exterior Rear View Mirror Control C527.
Measure the resistance between exterior rear view mirror control
C527 pin 7, circuit 544 (VT), harness side and passenger exterior
rear view mirror C622 pin A, circuit 544 (VT), harness side.
No
REPAIR the circuit.
TEST the system for
normal operation.
Yes
GO to B6 .
No
GO to B4 for driver
inoperative or GO to
B5 for passenger
inoperative.
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.
No
REPAIR the circuit.
TEST the system for
normal operation.
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