LR3/Disco 3
within 20 seconds.
On the initial selection of the windshield heater, the ATCM uses a short or long defrost phase at full power, followed by a
low power phase. The defrost phase used depends on the ambient temperature. During the low power phase, the
windshield heater relay is cycled off for 80 seconds and on for 40 seconds.
On subsequent operations, during the same ignition cycle, the ATCM operates the windshield heater at full power for a
fixed time period.
Windshield Heating Phases
MANUAL SYSTEM CONTROL DIAGRAM
NOTE :
Phase
Time, minutes
Short defrost (-5°C (23°F) and above)
3
Long defrost (less than -5°C (23°F))
5
Low power
10
Subsequent operation
3
A = Hardwired connections; D = High speed CAN bus; N = Medium speed CAN bus; O = LIN bus
