125002241 - E3030 HEATED REAR WINDSCREEN AND DOOR MIRROR DEFROSTING - DESCRIPTION

Description

If the visibility is poor it is possible to activate the defrosting of the rearscreen, the external rear view mirrors and the windscreen washer jets: the control button is located in the climate control system control unit and the command is sent to the Body Computer via the CAN.

The heating resistances for these components absorb a considerable amount of energy and they are therefore checked and deactivated after a certain period: the defrosting is timed, according to the following logic, managed by the Body Computer:

  • ignition ON (INT/A);
  • activation signal coming from the relevant button (or from the ''rapid demist'' function for the actual air conditioner).
In these circumstances the resistances remain supplied for a maximum of 20 minutes, then the power supply is cut off.

The power supply is also cut off under the following conditions:

  • ignition in OFF position;
  • disengagement signal from the button (or from the ''rapid demisting'' function);
  • battery voltage below 8.5 V
  • after the first 10 minutes operation, if the engine speed is below 950 rpm or
With the defrosting function on the warning light, in the climate control system control unit, connected to the Body Computer via the CAN, also comes on.The control logic also intervenes at the MAX-DEF command from the climate control: the defrosting function is activated for a maximum time of 7 minutes described previously (the deactivation of the MAX-DEF control only causes the heated rear windscreen to be switched off if the command to turn it on came from the MAX-DEF; if, on the other hand, the command came from the heated rear windscreen button, it remains on.The defrosting circuit is controlled by the heated rear windscreen relay and is protected by two fuses, one for the rearscreen and the other for the other resistance, all housed in the underdashboard control unit.