Chrysler RAM TRUCK 2500 1994 Service Manual page 523

8T - 8 POWER MIRRORS
•
AUTOMATIC DAY/NIGHT MIRROR
GENERAL
The automatic day/night mirror automatically
changes its reflectance to reduce glare i n all types of
driving conditions. A thin layer of electrochromic ma­
terial between two pieces of conductive glass make
up the face of the mirror. As light conditions change,
two photocell sensors adjust the reflectance while re­
ducing glare from headlamps approaching from the
rear.
SENSORS
The mirror incorporates 2 sensors. The ambient
sensor (forward facing) detects normal outside light
levels. The headlamp sensor (rear facing) detects
light levels received at the rear window side of the
mirror. When the difference between the two levels
becomes too great (light level received at rear of mir­
ror is much higher than front of mirror), the mirror
begins to darken.
SWITCH
The mirror switch controls whether the automatic
dimming feature is ON or OFF. When ON is selected,
the switch is lighted by an integral LED.
To test the operation:
• Turn ignition switch to the ON position.
• Place mirror switch i n ON (switch lighted) position
(Fig. 1).
FORWARD FACING SENSOR J948T-9
Fig. 1 Automatic Day/Night Mirror
DIAGNOSIS
Light sensor must be covered completely so
that no light reaches the sensor. Use one finger
pressed tightly against the sensor, or cover sen­
sor completely with electrical tape.
• Cover the forward facing sensor to keep out any
ambient light.
• Shine a light into the rear facing sensor. Watch to
see i f the mirror darkens.
With the mirror darkened, place the vehicle i n re­
verse, the mirror should return to its normal condi­
tion.
I f the above conditions are met the mirror is oper­
ating properly.
I f the above conditions are not met, perform the
following voltage tests (Fig. 1).
Test 3 way connector harness.
(1) Pin 1 - Ignition Switch i n RUN position, should
have battery voltage.
(2) Pin 2 - Should have continuity to ground.
(3) Pin 3 - When the transmission is i n reverse,
should have battery voltage.
(4) I f test is OK, replace Mirror.
(5) I f not, refer to 8W - Wiring Diagrams to test
the circuits.
REPLACEMENT
(1) Unplug connector behind mirror (Fig. 2).
MmM--^^
RELEASE
^ l mfcf
TAB
O N / O F F ELECTRICAL
SWITCH C O N N E C T O R J948T-8
Fig. 2 Automatic Mirror Removal
(2) Remove screw holding mirror to windshield.
(3) Push mirror up far enough to clear the support
and remove mirror.
(4) To install mirror, reverse removal procedures
REAR FACING SENSOR