LR3/Disco 3
EXTERIOR MIRRORS
The exterior mirrors on all models incorporate electrical heating and adjustment. Depending on vehicle model and market,
the exterior mirrors may also incorporate mirror foldback, memory recall and reverse dipping.
Heating
Exterior mirror heating is provided by heater elements bonded to the back of the mirror glass. The power supply to the
heater elements is controlled by the Automatic Temperature Control Module (ATCM).
The windshield washer jet heaters and the exterior mirror heaters are permanently enabled while the ignition switch is in
position II. The heaters are controlled by a 30 seconds period Pulse Width Modulated (PWM) signal from the ATCM to the
coil of the heated washer jets/exterior mirrors relay in the Battery Junction Box (BJB). When the relay is energized, it
connects a battery power feed to the heaters. To vary the time that power is applied to the heaters, the ATCM varies the
on-time percentage of the PWM signal, depending on the ambient air temperature and the status of the windshield
wipers. When the ignition switch is first turned to position II, the ATCM initially sets the on-time percentage of the PWM
signal to 100%, for a time that varies with ambient air temperature. After the initial heating period, the on-time percentage
varies according to the status of the windshield wipers.
Exterior Mirror Heating Percentage On-times
Adjustment
The exterior mirrors each incorporate two adjustment motors. One for horizontal (left/right) adjustment and one for vertical
(up/down) adjustment. Operation of the motors is controlled by the exterior mirror control switch, which is installed on the
mirror cheater of the driver door. Adjustment is enabled when the ignition switch is in position I or II.
The exterior mirror control switch is a combination rotary switch and joystick. Turning the switch left or right from the
central position selects the respective exterior mirror to enable adjustment. Tilting the switch connects a power supply and
ground to the appropriate adjustment motor to produce a corresponding movement of the mirror glass. When the switch is
tilted in the opposite direction the polarity of the adjustment motor connections is reversed, to move the mirror glass in the
opposite direction.
On vehicles with memory recall, the connections from the exterior mirror control switch to the adjustment motors are
routed through the seat control module. For additional information, refer to
Seats
(501-10 Seating)
Exterior Mirror Control Switch
On-times
Ambient Air Temperature, °C (°F)
<-10 (<14) -10 to 0 (14 to 32) 0 to 15 (32 to 59) 15 to 25 (59 to 77) 25 to 35 (77 to 95) >35 (>95)
Initial
-
100% for 3 minutes 100% for 2 minutes 100% for 1 minute 100% for 1 minute
-
Wipers Off
100%
75%
50%
25%
0%
0%
Wipers On
100%
100%
75%
50%
25%
0%
